Mazda 3 ECU swap question

[newguy90]

Hello everyone!
I have to replace the ECU of my Mazda 3, year 2003, 1.6 L gasoline. The one from my car is DENSO 279721-2240 and the ECU that I want to put in place is DENSO 279271-3990. Both ECU's are from the same type of engine (1.6 L , gasoline). Do you know if these two ECU's are compatible with each other? Can I safely make the swap?
The old ECU ( 279721-2240) has 93c56 EEPROM chipset (contains IMMO software) and the new ECU has S93A56 EEPROM chipset.
So, do anyone know if the IMMO code can be cloned from my old ECU to the new one?
Thank you!

[rafal]

why you can not to buy same ecu as ori?

[newguy90]

why you can not to buy same ecu as ori?
Actually, in the beginning, I did just that... I bought a used ECU with the same PCB code (279721-2240), and it turned out that the car has exactly the same symptoms like before the ECU swapping. I don't know if the second ECU has the same problem like my original ECU (could I be so unlucky? ), or if the problem is not the ECU. The Mazda dealer said that the culprit is definitely the ECU, because they couldn't find any other problems. So I manged to get a 3rd ECU ( the one with PCB Code 279721-3990), hoping that this will solve my car's problem. But, after I did some research over the internet about IMMO /ECU's & EEPROMS, I wonder if the IMMO software of these two ECU versions can be copied from one to another.
Thank anyone who can enlighten me on this matter!

[newguy90]

No one can help me? Really? :(

[kiszka]

No one can help me? Really? :(
you are aware that by making copies of the eeprom
you did a copy of the fault

[narkeleptk]

you are aware that by making copies of the eepromyou did a copy of the fault
Copy of the stored fault codes yes, copy of the faults themselves not likely.
What issue's do you have and what is your DTC's?

I do not know the cross reference for the ecu's programming but as far as the eeprom goes, read both and compare structure. If they look the same its probably ok. I would try only swapping immo related data tho.

[newguy90]

you are aware that by making copies of the eeprom
you did a copy of the fault

Ummm, I don't think so... As far as I know the 93c56 EEPROM holds just the IMMO and keys data. No DTC appeared after the ECU has been swapped, although the car was acting the same as with the old ECU!

[newguy90]

[FONT=Verdana]
Copy of the stored fault codes yes, copy of the faults themselves not likely.
What issue's do you have and what is your DTC's?


I do not know the cross reference for the ecu's programming but as far as the eeprom goes, read both and compare structure. If they look the same its probably ok. I would try only swapping immo related data tho.


I'm planning to do just that... I'm awaiting on my EEPROM programmer to arrive ( I ordered a cheap clip on EEPROM Programmer from china, so it takes a couple of weeks until arrival).
The issue is the following: The car died while coasting downhill and refused to start ever since. I pulled over and I plugged in the cars OBD a code reader and discovered 5 DTCs:
P0031
P0037
P0102
P0403
P0443
I've cleared them all, and then I tried to start the car. The engine cranks, but doesn't start. I took it to a Mazda dealer and after testing it for almost a day, dealer said that ECU is the problem... A new ECU is 2000 US dolars, so I took it home and I start investigating the problem myself. With the workshop the workshop manual and Autodata by my side, I checked fuses, wires, sensors resistance, voltages, checked for shorts to ground and batt+... almost everything I could think of!
What I found was: The ECU doesn't provide 12 volts to the following : Lambda sondes (1 and 2),EVAP, CMP, CKP, EGR, MAF and all 4 fuel injectors. All these sensors are wired to the ECU (ports 2T and 2BG) It only provides 12 Volts to the Ignition coils. As I said I checked all the inputs of the ECU (it receives 12V from Battery and Ignition) and all grounds are good also. If I take a live feed from battery and hook it to the MAF power wire the car starts and runs just fine, no DTCs at all! In fact I'm using the car hacked like this for almost a year now! :confused:
But I'm not comfortable knowing that something is wrong so that's why I want to try a new ECU to see if the car will be fixed, so that I will not need to drive a 'hacked' car ...
Any help will be appreciated! Thanks!

[narkeleptk]

I have not looked up any diagrams or into your problems so I may be wrong but you may want to double check yourself. Usually those type of control signals from ECU are ground signals and not 12V supplys.
Usually the 12V supply comes via a fused connection from fuse box.

also you do not need a programmer. just swap the chips around.

[newguy90]

I have not looked up any diagrams or into your problems so I may be wrong but you may want to double check yourself. Usually those type of control signals from ECU are ground signals and not 12V supplys.
Usually the 12V supply comes via a fused connection from fuse box.

also you do not need a programmer. just swap the chips around.

I don't want to mess something up in the process of unsoldering /soldering the EEPROM, so that's why I want to copy EEPROM contents. I think it's safer this way, don't you agree?
I attached the electrical diagram if you want to check it out.
Thanks!

[narkeleptk]

No fear of risk here either way sorry. I always desolder eeprom's to read them. I have never cared much for reading in-circuit with clips.

..
So you have the 12V supply to pcm but it does not activate the internal B+ circuits.
You ran a 12V jumper which powers the MAF and as a side effect it ended up activating the ecu's B+ circuits (i'm assuming since you said codes went away and runs normal)

Seems like an easy repair. Probably just a diode inside ecu bad where ever the B+ comes in.
OR
Since you said you tried other ecu with same results, it could possible be a wire break inside ecu harness where the wire joins the connector. These are hard to find sometimes because when your probing from back of connector you will test before the break and when you test from the front you can push the terminal just enough to make the connection for false read.

If you where using a DMM then sometimes hairline breaks in the wires will still read as 12V but fail under load. Make sure to try testing the b+ supply on connectors terminal side using a test light to simulate load.

[newguy90]

I didn't probe from the wires side of the ECU connector, but from the ECU side by carefully inserting a thin needle in the connector pin holes using an Digital Ohmeter, of course. I found no breaks, shorts to mass or B+ as I previously said. I wil try to check all the ECU harness again by using a test lamp this time, as you suggested.
I also tested for continuity between 2T , 2BG and injector's pins (2E, 2F, 2G and 2L) of the new ECU which I want to put in the car after I'll copy the IMMO from the old one, and I found that all of them are connected (0 ohms between all of them).
So I wonder what could be the problem? Is it a bad diode insde the ECU, like you said, or maybe a false signal / missing signal which makes the ECU to stop from feeding 12 v to all of the sensors/parts mentioned in my previous message?
The only other thing which I could find is that the voltage at the CLUTCH SWITCH (1P) and NEUTRAL SWITCH (1AB) is only 5.91 volts, instead of B+ as it should be according to the workshop manual.

[narkeleptk]

Do you have any pictures of ecu's pcb?

[kiszka]

.............

[newguy90]

Here are the pics of the 'new' ECU's PCB... sorry for the delay!
The blown up picture shows the EEPROM S93A56 which holds the IMMO data.

[newguy90]

..and here is the pic with the 'old' ECU's EEPROM 93C56:

[narkeleptk]

I was really only interested in the pcb for the bad unit but your "new" unit has no zener installed and looks to be left off by design, that is pretty odd they chose to do away with the over voltage protection even tho the footprint was already there..

[newguy90]

Yes, no limitation for the voltage... That's why the diagram shows B+ for the voltage, otherwise they would have put the a fixed value of 12V., don't you agree? Likewise, in Autodata 3.45 the B+ has a value of 11-14 V... So again that means it's not a fixed value of 12 V.

[narkeleptk]

I'm sorry its actually referred to as a TVS diode and really nothing to do with your current issue, I was just pointing it out because I thought it was a bit odd. If you look at your old ecu you will see it has one, yet the replacement ecu does not. The ecu will function as normal with out it but you run higher risk of transient voltages ravaging the ecu.

TVS Diodes only blocks voltages if they go to high from coming in. Around 19-26V's is typical on 12V systems. This prevents the higher voltage's from outside the ecu coming in and blowing up the lower rated components, like those 35V caps which would be on the B+ line and even those 10V caps on the mcu power supply side if things went really bad. I would install one myself personally, Maybe this one SM8S22A. It has a working voltage of 22V and breakdown around 25V.

B+ is just what ever your battery/alternator is putting out so yes it will range from 11-15V but people tend to just refer to these things as 12V for simplicity.

[newguy90]

I don't know that much about electrical components, just the basics... that's why I prefer to do "software mod" instead of a hardware mod.. . :)
Did you take a look at the specs for the two EEPROMs mentioned before? ( A93c56 and S93A56) As far as I see, both of them have the same pin structure /functions , so I think that (with a bit of luck) the cloning of the IMMO data can be susccesful. I hope. :smile-new:

[narkeleptk]

Yes they have the same pinout

[Meat-Head]

Not going to argue as the pcb images not clear enough to me, be have found that some cars the ecu is used as a junction point

power in/out.

sounds to me, but won’t argue the pcm relay is bad, or one of them fuses is missing?

if it has been ok for a year more likely something gone open circuit

can you swap fuel and pcm relays over

[newguy90]

@Meat-head:
By PCM relay, do you mean MAIN RELAY? Swapping the main relay with the pump relay was one of the first things I did. Also, as I previously said, I cheked every single ECU harness wires for open circuit / short to mass / short to Batt+. I didn't find anything wrong.:confused:

[Meat-Head]

Remove the main relay, feed airflow meter, start indain and see what voltage you got on all pins.

[kiszka]

Remove the main relay, feed airflow meter, start indain and see what voltage you got on all pins.

there will definitely be bad tension


@Meat-head:
By PCM relay, do you mean MAIN RELAY? Swapping the main relay with the pump relay was one of the first things I did. Also, as I previously said, I cheked every single ECU harness wires for open circuit / short to mass / short to Batt+. I didn't find anything wrong.http://www.digital-kaos.co.uk/forums/images/smilies/confused.png

from fuse F34 (on output)
or F69 20A engine compartment
if it catches the air flow meter error on F34
make a bypass with a wire to the flow meter
use the correct thickness of wire, for the length of the wire
and believe me you'll forget about the fault forever

[newguy90]

Remove the main relay, feed airflow meter, start indain and see what voltage you got on all pins.
Sorry, but I can't figure it out what do you mean by "start indain" :confused:

[newguy90]

@kiszka:
At first I did something similar (I fed B+ from F34 not only to the MAF but to the CKP also (to avoid overloading of the ECU's circuitry) and the result was : engine died in a winter night on the way home ... not very pleasant ;) ... Luckly, I was only a few miles away from home, so I called a friend to tow my car home. Only the next day I discovered the culprit: F69 fuse (20A) from the PJB (Passenger Junction Box) was blown! I replaced the fuse and the car started without any issues. To avoid this kind of problems, I decided to make a separate power source, so I used a relay which when is triggerd by the ignition it feeds the MAF sensor and the CKP sensor with B+ directly from the battery through a 10A fuse. No more blown up fuses from that moment.
... But still... I can't just "forget about the fault forever" . Sometimes on occasion, the engine cuts when I rev it above 4000 rpms (not all the time , though) , and strangely just today I felt a brief engine cut just after I passed over some bump with my rear wheels at low speed! :confused:
So that's why I can't just ignore this problem... I need to get to the bottom of this, somehow.

[Meat-Head]

Indian, as in engine.

reading that, somewhere, is a tiny tiny chaffed wire, which has blown away.

find the nearest bumpy road, hit it fast see if fuse blows.

chances are something silly like injector loom rubbing when engine cover moved?

[newguy90]

Indian, as in engine.
reading that, somewhere, is a tiny tiny chaffed wire, which has blown away.
find the nearest bumpy road, hit it fast see if fuse blows.
chances are something silly like injector loom rubbing when engine cover moved?

No fuses blow whatever bumpy road I'm on. Only yesterday I felt an engine brief "hiccup" when I passed with the rear wheels over some bump at low speed.

[electronico]

I'm planning to do just that... I'm awaiting on my EEPROM programmer to arrive ( I ordered a cheap clip on EEPROM Programmer from china, so it takes a couple of weeks until arrival).
The issue is the following: The car died while coasting downhill and refused to start ever since. I pulled over and I plugged in the cars OBD a code reader and discovered 5 DTCs:
P0031
P0037
P0102
P0403
P0443
I've cleared them all, and then I tried to start the car. The engine cranks, but doesn't start. I took it to a Mazda dealer and after testing it for almost a day, dealer said that ECU is the problem... A new ECU is 2000 US dolars, so I took it home and I start investigating the problem myself. With the workshop the workshop manual and Autodata by my side, I checked fuses, wires, sensors resistance, voltages, checked for shorts to ground and batt+... almost everything I could think of!
What I found was: The ECU doesn't provide 12 volts to the following : Lambda sondes (1 and 2),EVAP, CMP, CKP, EGR, MAF and all 4 fuel injectors. All these sensors are wired to the ECU (ports 2T and 2BG) It only provides 12 Volts to the Ignition coils. As I said I checked all the inputs of the ECU (it receives 12V from Battery and Ignition) and all grounds are good also. If I take a live feed from battery and hook it to the MAF power wire the car starts and runs just fine, no DTCs at all! In fact I'm using the car hacked like this for almost a year now! :confused:
But I'm not comfortable knowing that something is wrong so that's why I want to try a new ECU to see if the car will be fixed, so that I will not need to drive a 'hacked' car ...
Any help will be appreciated! Thanks!

Hello,
(sorry for thread hijacking)
I have the same issue with the same ECU on the same car.
Trying to put hand on some wiring diagrams, especially ECU pinouts (as I only have the ECU for repair right now).
Thanks a lot if you can help.
Be sure I'll keep you informed if I solve the problem.

EDIT : Mazda dealer service told : "no power to fuel pump => ECU"
I'm not aware of any DTC he might have found

[newguy90]

Hello,
(sorry for thread hijacking)
I have the same issue with the same ECU on the same car.
Trying to put hand on some wiring diagrams, especially ECU pinouts (as I only have the ECU for repair right now).
Thanks a lot if you can help.
Be sure I'll keep you informed if I solve the problem.

EDIT : Mazda dealer service told : "no power to fuel pump => ECU"
I'm not aware of any DTC he might have found

What do you mean by "same issue"? Car cranks but doesn't start? When you turn the ignition to ON, do you hear the Fuel pump working ?
Can you explain your problem in more detail?
If you need the wiring diagram of the mazda 3 , you can find it in my #10 message from this post.
From the wiring diagram you can see that Fuel Pump relay (K20) gets its power directly from the car battery through F24 fuse, and it feeds 12V to the fuel pump.
ECU is controling the Fuel pump with the help of the Fuel pump relay (ECU grounds the fuel pump relay). This is done by ECU through 1AC pin .

You must check the continuity / short to ground/ short to power of the fuel pump. I attached a document from the Mazda Workshop manual for you (FUEL PUMP UNIT INSPECTION [ZJ, Z6, LF]).

[electronico]

Hello,

Thanks for your inputs !

I came back to car.
Fuel pump relay is well activated and fuel pump 12v supplied.
Engine cranks, but no start.
Supplying a 12V on PCM 2T pin allows car start.
I'll enquiry about PCM, trying to fix it.

[newguy90]

Then why did your mazda dealer say that your car's pump fuel it's not powered ? (your Mazda dealer service told you : "no power to fuel pump => ECU").
So you don't have any power on 2T ECU pin? That means you have indeed the same problem like I have. Not only 2T has no B+, like it should, but also 2BG, 2E, 2F, 2G and 2L of the ECU pins. As far as I know, all those pins are connected to each other, so the ECU doesn't feed 12V (or B+) to the MAF, EGR, HO2S1, HO2S2, EVAP, and fuel injectors. ... Can you confirm that?
What voltage do you have on pin 1AB and pin 1P when the ignition is ON? Also, can you tell me what's the electrical resistance between 2T pin and 2BH pin of your ECU (measured when ECU is disconnected)?

[electronico]

Then why did your mazda dealer say that your car's pump fuel it's not powered ? (your Mazda dealer service told you : "no power to fuel pump => ECU").
So you don't have any power on 2T ECU pin? That means you have indeed the same problem like I have. Not only 2T has no B+, like it should, but also 2BG, 2E, 2F, 2G and 2L of the ECU pins. As far as I know, all those pins are connected to each other, so the ECU doesn't feed 12V (or B+) to the MAF, EGR, HO2S1, HO2S2, EVAP, and fuel injectors. ... Can you confirm that?
What voltage do you have on pin 1AB and pin 1P when the ignition is ON? Also, can you tell me what's the electrical resistance between 2T pin and 2BH pin of your ECU (measured when ECU is disconnected)?

I can't tell for the Mazda dealer, that's what he told to the end-user.

Yes all these pins are connected together on the ECU.
I have brought only the ECU back to bench, so can't measure anything on car right now.
2BH is GND and I read infinite resistance between 2T and 2BH, which is normal.

Up to now I haven't found any destination on ECU for these 2T - 2E - 2F - 2G - 2L - 2BG pins, so I wonder if these B+ missing line isn't wired out of the ECU.

Looking at the schematic, pins 1BB - 1BC - 1BF - 1BG should be connected to B+ but they are not on the ECU itself.
And this B+ line goes to Vehicule Speed Sensor too.

Next week will be off for me, so next tests on August 24th.

[newguy90]

I can't tell for the Mazda dealer, that's what he told to the end-user.
2BH is GND and I read infinite resistance between 2T and 2BH, which is normal.
Up to now I haven't found any destination on ECU for these 2T - 2E - 2F - 2G - 2L - 2BG pins, so I wonder if these B+ missing line isn't wired out of the ECU.
Looking at the schematic, pins 1BB - 1BC - 1BF - 1BG should be connected to B+ but they are not on the ECU itself.


Hm.. Now I'm confused... My old ECU, which is on the car now, has infinite resistance between 2T and 2BH pins, but my new ECU which I bought to replace the old one shows 0.775 ohms when I measure with the multimetre set on 2 Kohms reading!
If you say infininte is good, then colud my new ECU be bad?? I'm lost.


About the 1BB - 1 BC - 1BF- 1BG ... NO, they don't have to be all connected to B+, because 1BC and 1BG are for the automatic shift version of Mazda 3, not for the manual shift version.

You said that B+ line goes to vehicle speed sensor? Do you mean CKP sensor? Or the speed sensor inside Instrument cluster?

I am taking a short vacation too for the next 10 days, so good relaxation to us.... and to all others who need it . :)

[narkeleptk]

Hm.. Now I'm confused... My old ECU, which is on the car now, has infinite resistance between 2T and 2BH pins, but my new ECU which I bought to replace the old one shows 0.775 ohms when I measure with the multimetre set on 2 Kohms reading!
If you say infininte is good, then colud my new ECU be bad?? I'm lost.

Your "new" ecu is completely different hardware from your old one if its the same pictures you posted, you would not be able to compare them.

[newguy90]

I hope you're right, narkeleptk! 😁

[electronico]

Hm.. Now I'm confused... My old ECU, which is on the car now, has infinite resistance between 2T and 2BH pins, but my new ECU which I bought to replace the old one shows 0.775 ohms when I measure with the multimetre set on 2 Kohms reading!
If you say infininte is good, then colud my new ECU be bad?? I'm lost.



About the 1BB - 1 BC - 1BF- 1BG ... NO, they don't have to be all connected to B+, because 1BC and 1BG are for the automatic shift version of Mazda 3, not for the manual shift version.

You said that B+ line goes to vehicle speed sensor? Do you mean CKP sensor? Or the speed sensor inside Instrument cluster?
The model I work on is an automatic shift version.
You're right, it seems Vehicule Speed Sensor is only for ATX (Automatic Shift).


I am taking a short vacation too for the next 10 days, so good relaxation to us.... and to all others who need it . :)

I have attached the PCM (ECU) wiring diagram I found.
Strange thing (for me) is :
- Why is the B+ line called :
'i' on pins 1BB 1BF 1BG
'e' on pin 1BC
'g' on pin 2BG
There must be things between them, or they would be called by the same letter.

Attached on-board diag through radio, mainly because I can't see any default (they have been cleared by previous techs) with my generic VCI, I'll test this ASAP.

[electronico]

So :
Wiring a 10A fuse between ( 1BB 1BC 1BF 1 BG ) and ( 2BE 2BF 2BG 2L 2T ) allows car start.
Car seems to be in degraded mode with MIL lit (4000 rpm max).
I should have car at end of week to test better.

[newguy90]

Hello! I'm back from the vacation... So let's get to work. :)


Strange thing (for me) is :
- Why is the B+ line called :
'i' on pins 1BB 1BF 1BG
'e' on pin 1BC
'g' on pin 2BG
There must be things between them, or they would be called by the same letter.



Those things baffled me too at first glance, but I realized they are indexes of the connections (the Mazda guy didn't want to over_lap lines in the diagram :) )
So, the "i" on pin 1BB, 1BF, 1BG is actually a "f" (poor graphic file) and indicates that is connected to the"f" from Main Relay and Fuel Pump ( a bit lower and to the right on the same diagram page).
The "e" of the pin 1BC indicates that is connected to the VSS terminal noted with the same letter "e" .
And, lastly, the "g" on the pin 2BG is connected to the "g" terminal of the MAF Sensor.
I attached the two pages diagram modified by me, if it helps.




Attached on-board diag through radio, mainly because I can't see any default (they have been cleared by previous techs) with my generic VCI, I'll test this ASAP.


If the trouble codes were previously cleared, you won't find them anymore. But if you want to replicate them, then all you have to do is :
1) turn the ignition to ON,
2) feed B+ from the 1BE (IG1 = ignition) to both (or at least one) of the output lines (2T / 2BG),
3) turn the key to start the engine (the engine should start, and run without any issues or DTC's - at least my car's engine works fine, and it revs without any issues - it doesn't lit the MIL and no rev limitation, until the 6500 rpm, of course)
4) while engine running, disconnect the feed line connected as indicated at step 1). When you remove the B+ feed line, the engine will stop, and the following DTC's will show up: P0031, P0037, P0102, P0403, P0443.


NOTE 1: Don't run the engine for long periods if you connect the B+ feed to just one of the output lines (2T/2BG) or you may burn the circuits inside the ECM due to overloading.


NOTE 2: If you encounter errors when you power the car using a B+ feed line like I told you above, and the MIL is lit, read the DTC codes and let me now what you have found.


p.s. When you will have the car for testing, can you verify also the voltage you get at pins 1P and 1AB (with the ECM connected) as I previously asked you? The mazda workshop manual shows B+ at those pins, but my car has only 5.91 V! Thanks!

[electronico]

Hi,
Sorry for the late reply,
I should have had car for testing this week-end, but I had to schedule to next one because of urgent works.
Be sure I'll let you know how it goes.
Customer complains mainly with bad automatic shifting and power lack (this last felt by me while testing).

[newguy90]

How are you , electronico? Did you managed to test the car yet?

[electronico]

Hi, I have the car, but have many urgencies to deal with before having a look.

[electronico]

Well,
Forcing B+ to 2E went OK.
2E is wired to 2BG on ECM.
Car was well running as usually.
After 40km drive, the 2E to 2BG track fused.
Replaced it with a thin wire : blown again.
Wired a 20K resistor between 2E and 2BG : still got 0 Volt at 2BG.
2BG is for sure the problem.

About your asks,
1P was 4.91V
1AB was 6.91V
(automatic shift)

I gave up and loose 2 days of work on these, won't see car again.

[Meat-Head]

So either something silly like lamda sensor rubbing once in a while to earth or something
simular, sounds like second time it’s blown a hidden track as your thin wire was too ‘thick’

great To read about stuff like this, nice when car comes in the same and great for pub quiz question

thanks

[newguy90]

Well,
Forcing B+ to 2E went OK.
2E is wired to 2BG on ECM.
Car was well running as usually.
After 40km drive, the 2E to 2BG track fused.
Replaced it with a thin wire : blown again.
Wired a 20K resistor between 2E and 2BG : still got 0 Volt at 2BG.
2BG is for sure the problem.

About your asks,
1P was 4.91V
1AB was 6.91V
(automatic shift)

I gave up and loose 2 days of work on these, won't see car again.

Why did you feed B+ only to the 2E? I told you that if you do something like that for long periods, the ECU wil get fried! You should have fed B+ to 2BG AND 2T. That way the car can be used without any problems. I use mine like this for over 5000 km now, without any (obvious) issues. No melting of circuits, no DTC's , revving just fine even past 6000 rpms.
Thanks for taking the time to measure the voltage at 1P and 1AB. As I said my car has 4.91 V at those pins.
Do you have any ideea why it has 4.91V / 6.91 V instead of B+, like the Mazda Workshop Manual indicates?

I finally got the mini EEPROM programmer from China, but ... surprise... I can't just plug in the EEPROM in the programmer zif socket and copy the content 'cause it's designed mainly for the 24Cxx and 25cxx EEPROMS. So I need to find out how can I program my 93C56 /93A56 chip.

[Meat-Head]

Might be easier to take that ecu to local “car radio decoding shop” or “digital mileage IN-correction company”

Have a look in the airbag or mileage section for a member called “L J wood” I think he’s in NJ if it helps.

[electronico]

2BG and 2E are connected together on PCB, supplying B+ to 2BG or 2E is the same thing.
Car ran without limitation on rev, neither MIL lit, so it was OK.
About your eeprom programmer, what model is it ? You need SOP-8 (or SSOP-8, I don't remember) to DIL adapter.

[narkeleptk]

I finally got the mini EEPROM programmer from China, but ... surprise... I can't just plug in the EEPROM in the programmer zif socket and copy the content 'cause it's designed mainly for the 24Cxx and 25cxx EEPROMS. So I need to find out how can I program my 93C56 /93A56 chip.

That little one on usb stick with zif socket? Its only for 24/25 series so it will not red 93c56. You need another reader.

I reccomend : http://www.xgecu.com/en/TL866_Dealer.html
OEM on ebay: https://www.ebay.com/itm/XGecu-TL866II-Plus-USB-Programmer-for-SPI-Flash-NAND-EEPROM-8051-MCU-4-adapters/221072202503?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[newguy90]

2BG and 2E are connected together on PCB, supplying B+ to 2BG or 2E is the same thing.
Car ran without limitation on rev, neither MIL lit, so it was OK.
Yes, 2BG and 2E are connected together, but because of the big current needed, if you feed B+ only to 2BG or 2E you risk to overload a part of the circuitry! If you have had connected B+ to 2E/ 2BG and 2T, no melting would have happened. I guarantee that!


About your eeprom programmer, what model is it ? You need SOP-8 (or SSOP-8, I don't remember) to DIL adapter.
I bought the CH341a MiniProgrammer (black mobo) with a SOIC8 test clip. The problem is that the pinout of the mini programmer doesn't correspond to the 93c56 pinout. As you can see on the back of the programmer (picture attached) it is mainly designed to work with 24cxx and 25cxx EEPROMs. Those have different pinout than 93c56 so I can't just directly connect the 93c56 and programm it. I think I need to re-wire the 93c56 pin's using dupont wires to fit the layout I need. So I think the correspondence between 93c56 and CH341a side pins should be: CS to CS, CLK to CLK, MOSI to DI, MIOS to DO, 3.3V to Vcc, GND to GND. Would that be ok?
652421

[newguy90]

That little one on usb stick with zif socket? Its only for 24/25 series so it will not red 93c56. You need another reader.



The adlisting on the website from which I bought the programmer said it can be used for 93cxx, 24cxx and 25cxx programming. That's why I bought it.

[narkeleptk]

The adlisting on the website from which I bought the programmer said it can be used for 93cxx, 24cxx and 25cxx programming. That's why I bought it.
Its probably a typo and meant "95xxx"

Is 93c56 listed in the software? If not just swapping the wire's probably will not work. They read and write different ways.


https://www.digital-kaos.co.uk/forums/attachment.php?attachmentid=652487&d=1569067492


93xxx: https://www.mouser.com/datasheet/2/308/fairchild_FAIRS07593-1-1191746.pdf
25xxx: http://ww1.microchip.com/downloads/en/devicedoc/doc0606.pdf

[newguy90]

Its probably a typo and meant "95xxx"

Is 93c56 listed in the software? If not just swapping the wire's probably will not work. They read and write different ways.



It's not a typo... Here are some search results : https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190921052027&SearchText=ch341a+93cxx&switch_new_app=y

I couldn't find 93cxx in CH341a software, but I found it in AsProgrammer 1.4.

[narkeleptk]

If original source made the typo then all the sources will carry that typo. Ali sellers usually know nothing of what they are selling. 95xxx is same as 25xxx pretty much so it makes more sense for this device. I could find no information of anyone using the device for 93xxx but i didn't look that hard either.

I would test it on another 93c56 first to prevent corruption of your original ecu's one.

[newguy90]

I would test it on another 93c56 first to prevent corruption of your original ecu's one.

That's what I'm plannig to do first...I'm testing it on a 93c46 . I couldn't find a 93c56 at the local shop, but it's almost the same thing, just different memory size .

[newguy90]

It's not working! I tried to read /write the 93c46 EEPROM (using Ch341a and AsProgrammer 1.4), and it fails both of the operations. I tried using +5V for Vcc and after that the +3v for Vcc. No success ... :(

[newguy90]

Well, I've done it! I built myself an adapter (interface) for programming of the 93cxx eeproms and use that with Pony Prog. So, I managed to read and write the ECU's EEPROM without desoldering it from the ECU. Yyy-haa!! :)
But now I'm facing an unexpected situation. The data read from my old ECU (burnt from mistaken) contains a different VIN number than the one of my car! Maybe the technician who should just copy the EEPROM content from this old ECU to my current ECU installed in the car had in fact swapped the EEPROMs of the two ECUs??
I don't see any other explanation... You can't trust almost anybody these days... :(
If that's the case I will have to take the ECU off my car read the IMMO data from it and than to write that data into the new ECU.

[narkeleptk]

Sounds like the mechanic did not bother to flash the vin to the pcm. This would not effect the running of the car just would cause some vin mismatch codes. Probably did parameter reset and diagnostically. Doubt he did any eeprom work or he would have transferred the entire 93c56 dump vin included. The key programming and vin programming are two separate things so when he had the same problems with replacement ecu as the original after key programming probably felt it was no point in flashing VIN.

The VIN is easy enough to just edit into the dump manually.

[newguy90]

The thing is I took the two ECUs (old + new) to a guy asking him to copy the IMMO data from the old ECU to the new one...I guess he couldn't do that, or he just felt more comfortable to swap the EEPROMS between the two ECUs! And he didn't bother to tell me what he did and charged me for IMMO software cloning ! Nice going, huh? I could have done that myself and save the money, If I would have been told what he's planning to do...

[narkeleptk]

I still not sure I follow you. You have ecu-ori, ecu-donor 1 and a new ecu-donor 2 you need to write.
I think your saying you took ori + donor-1 to a guy to clone. Now you are reading ori and it has incorrect data, correct?
If so, then yes he probably was lazy and just swapped chips instead of reading then writing to donor-1. Bad practice imo, but in fairness to the guy its usually ok to do it this way.
Do you still have donor-1?

What region is this car in?
We have Mazda's here around that year with either a separate immo box or PATS in the cluster. The ecu usually just has a type of sync code with box or cluster, Is that what yours is or is yours have all immo data stored in ecu?

[newguy90]

I still not sure I follow you. You have ecu-ori, ecu-donor 1 and a new ecu-donor 2 you need to write.
Correct! "Ecu-ori" - burnt ( it's a long story) , "Ecu-donor 1" (currently on the car, but car just cranks, doesn't start just like "ECU-ori" - as I explained in my post), and "ECU-donor3" (the one that I bought to replace the "ECU-donor 1" to see if somehow the "ECU-donor 1" is defective,too.




I think your saying you took ori + donor-1 to a guy to clone. Now you are reading ori and it has incorrect data, correct?
If so, then yes he probably was lazy and just swapped chips instead of reading then writing to donor-1.

Correct again! When I read the ECU -ori I found a VIN number of another type of mazda, not my original VIN number. Also I looked closely with a magnifier at the EEPROM's pins and I think the soldering differs from the soldering of the other electronic parts... So, yes he definitely switched the EEPROMs, although he still denies he did that!




Bad practice imo, but in fairness to the guy its usually ok to do it this way.
Do you still have donor-1?

Yes, it's ok to do it that way, too, but as I said he should have been fair and told me what he intends to do, not to lie. What would have happened now if instead of doing this operation myself (copy EEPROMM content from ECU-ori to ECU-donor 2) I went to a service shop and paid for their service? Money thrown out the window, right? And this just because he "forgot" a little detail like telling me that my ori ECU doesn't have the original EEPROM anymore...




What region is this car in?
We have Mazda's here around that year with either a separate immo box or PATS in the cluster. The ecu usually just has a type of sync code with box or cluster, Is that what yours is or is yours have all immo data stored in ecu?
My car has PATS in the cluster that needs to sync with the data in the ECU. In this weekend I'll take off the ECU-donor 1 of my car and copy the EEPROM's data from it to the new ECU (donor 2). And after that, the moment of truth... :) But, I'm afraid of that! Why is that? Although I checked, and checked again the electrical harness for shorts, sensors' resistance, voltages and what not , I still have doubts... What if "something" is wrong with the car harness/parts and when I will put the new ECU in the car and attempt to start, the engine will just crank and not start, and that "something" will damage the new ECU? Is this a possibility or not? If the answer is yes, what can I do to avoid it?

[narkeleptk]

Well if the PATS is in the cluster then it's simple just write your VIN number in the eeprom of donor2 and do a parameter reset diagnosticly

[electronico]

Hi,
The content of the 93c56 I read shows the VIN, you have to reverse bytes to read it correctely.
Mine is present from x46 to x57 and is read like this :
47 46 49 48 4B 4A 4D 4C 4F 4E 51 50 53 52 55 54 57 56
I don't know if there is a checksum or such in file.

EDIT : Oooops, I was reading device dump in 8 bits mode ... reading it in 16 bits mode well shows the VIN in clear text.
Sorry to have made confusion.

[newguy90]

Hi,
The content of the 93c56 I read shows the VIN, you have to reverse bytes to read it correctely.
Mine is present from x46 to x57 and is read like this :
47 46 49 48 4B 4A 4D 4C 4F 4E 51 50 53 52 55 54 57 56
I don't know if there is a checksum or such in file.

My ori ECU contains this mazda VIN number: JMZBK14Z201124300 which is not my car's VIN (like I previosuly said, the guy who should just copy the EEPROM's content from Ori to Donor 1 did in fact a swap of the EEPROMs ). I don't have to reverse anything to read it. Here is the full dump of the EEPROM:

[newguy90]

Well if the PATS is in the cluster then it's simple just write your VIN number in the eeprom of donor2 and do a parameter reset diagnosticly

Hm...The IMMO is in the Cluster (if by PATS doesn't mean IMMO, then I was wrong when I answered your previous question). So, the ECU's EEPROM contains the VIN and probably the keys and some other info.. . ? Look at my dump of the Ecu ori and see if you can figure out what's in it, please.
What do you mean by "parameter reset" ? how can I do that?

[narkeleptk]

PATS is the immobilizer yes.
The ecu dump you provided has no keys so it will only have a verify code placed in it from the PATS (in cluster). When you do a parameter reset your telling the PATS you replaced the PCM and to change the verify code in it. For the immobilizer this is all you need to do.

The VIN you either need to flash update the pcm diagnostically or manually write it in the eeprom.

[newguy90]

I took the Donor 1 ECU off of my car and copied the EEPROM's data to the new Donor 2 ECU. This one (Donor 1) contains the correct VIN number of my car ! Then I installed the Donor 2 in the car, crossed my fingers, said a prayer and ..Ignition ON - Start Engine. And the engine started...no other B+ hack needed! But there were some lights turned on in dash (check engine, DSC etc) so I turned it off quickly to insert the OBD ELM327 to read the errors.
The following DTC's showed up in my Torque app:
(Pending Fault) P0102 - Powertrain - Mass or Volune Air Flow Circuit Low Input
(Pending Fault) P0138 - Powertrain - O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
(Pending Fault) P2088 - Powertrain - A Camshaft Position Actuator Control Circuit Low bank1 b)
I installed back the ECU Donor 1 fed B+ to the MAF and CKP so I can start the car with this defective ECU, turned On the engine and no DTC's were present. I think that those 3 DTCs were in the ECU from the originating car.
So I then reinstalled the new ECU (Donor 2) , fired up the engine and I pulled the DTC's again. This time the P0102 was gone, only the rest were still there. This time I cleared the DTCs and then I read them one more time... now there was only one error remaining: P0138!
What could be wrong? The Lambda Sonde no. 2 is fine, i think ... no errors when i use the ECU Donor 1... Why this DTC shows up with the new ECU Donor 2? :distress:

[narkeleptk]

It could be hardware mismatch in ecu considering it was a different version. I would ignore it for a while see if it goes away, hoping its just remembering its last engine. If it does not go away you could try a flash update. Might be worthwhile to measure the resistance of this circuit in the old ecu, and compare it with what is in the new one. It would be helpful if you have a oscilloscope to check the signal.

[newguy90]

I checked the resistance between 2K pin and 2AX pin (the control part of the Lambda Sonde 2) and it's different between the 2 versions of ECU's. The Donor 3 ECU has only 1.29 Mohms, and the Ori ECU has 1.5 Mohms. But same goes for the Lambda sonde 1, and I get no error there! I'll double check the voltages / short to power according to the worksop manual and see what's going on after I'm driving the car a few km. I let you know how it goes.

[newguy90]

Today, when I started the car with the new ECU (Donor 2) the engine was running rough and two errors showed up: P0103 and P2088 and the ESP light and Check Engine light were on. Several times I cleared them and they reapeared right back. So I took the car out for a drive, and after a few km the ESP light went off, and I cleared the errors and they didn't reapeared. Also the engine was not running rough anymore. After 15 km I stopped and when I started the engine the error P2088 showed up again. If I clear it it stays cleared until I stop and start the engine again. It shows up both in yellow (Pending DTC) and grey (Torque sais:" gray fault codes might only be clearable by the ECU itself after 'N' fault-free drive cycles have completed" )
The Mazda worksop manual: DTC P2088 - "Variable valve timing control circuit low " - possible causes:
• OCV malfunction
• Connector or terminal malfunction
• Open circuit in wiring harness between OCV terminal A and PCM terminal 2AK
• Short to GND in wiring harness between OCV terminal A and PCM terminal 2AK
• Open circuit in wiring harness between OCV terminal B and PCM terminal 2AG
• Short to GND in wiring harness between OCV terminal B and PCM terminal 2AG
• PCM malfunction
I will check those things tomorrow cause I haven't got the nerves to do it today... I hope it's not the last one, though, 'cause I've had it with bad PCMs... :)))
I'll have a word or two "from heart to heart" with the guy who sold me a year ago the bad ECU (donor 1) as a "good working ECU". Because of him, I've waisted my time and others trying to find what other things than ECU might be the problem of my car's "cranking, but not starting" engine situation.

[newguy90]

Unfortunately, I have bad news. Although at first it seemed that almost all is ok with the new ECU swap, it seems that the two versions (279721-2240 and 279721-3990) are not fully compatible.. At least this is my conclusion. Any time I start the car (cold engine), it runs rough, and 3-4 DTC's comes up:
P2088, P0103, P0335 and U2023. I clear them and after a few seconds some / all of them reapear right back. So either they are not compatible, or the new ECU (Donor 3 ) has some problems itself.
Does ANYONE here can tell me if those two types of ECU are compatible with each other or not?
I'm at my wits end here.... I'm afraid I'm gonna need to start looking for a new 279721-2240 ECU... :(

[narkeleptk]

you need find out what calibration is on the PCM and then you need to see if this is compatible with your car.Jf its not you need to reflash the PCM with the latest calibrations for your build

[newguy90]

how can I find out what calibration is on the PCM?

[narkeleptk]

A good scan tool is the easiest way.

[bubad]

Hi, I don't suppose you could send me the to Mazda 3 control system wiring diagram and the electrical diagram autodata 3.45 PDF please as I can not seem to get them to download from your post in august 5th 20019 post...

[kiszka]

Hi, I don't suppose you could send me the to Mazda 3 control system wiring diagram and the electrical diagram autodata 3.45 PDF please as I can not seem to get them to download from your post in august 5th 20019 post...
P2088 A Camshaft Position Actuator Control Circuit Low Bank 1

[Dangar]

Hello everyone!
I have to replace the ECU of my Mazda 3, year 2003, 1.6 L gasoline. The one from my car is DENSO 279721-2240 and the ECU that I want to put in place is DENSO 279271-3990. Both ECU's are from the same type of engine (1.6 L , gasoline). Do you know if these two ECU's are compatible with each other? Can I safely make the swap?
The old ECU ( 279721-2240) has 93c56 EEPROM chipset (contains IMMO software) and the new ECU has S93A56 EEPROM chipset.
So, do anyone know if the IMMO code can be cloned from my old ECU to the new one?
Thank you!

I'm new to the forum and jumping on this thread. Need to figure out which chips to swap for an ECU replacement.

[liviu2010]

I'm planning to do just that... I'm awaiting on my EEPROM programmer to arrive ( I ordered a cheap clip on EEPROM Programmer from china, so it takes a couple of weeks until arrival).
The issue is the following: The car died while coasting downhill and refused to start ever since. I pulled over and I plugged in the cars OBD a code reader and discovered 5 DTCs:
P0031
P0037
P0102
P0403
P0443
I've cleared them all, and then I tried to start the car. The engine cranks, but doesn't start. I took it to a Mazda dealer and after testing it for almost a day, dealer said that ECU is the problem... A new ECU is 2000 US dolars, so I took it home and I start investigating the problem myself. With the workshop the workshop manual and Autodata by my side, I checked fuses, wires, sensors resistance, voltages, checked for shorts to ground and batt+... almost everything I could think of!
What I found was: The ECU doesn't provide 12 volts to the following : Lambda sondes (1 and 2),EVAP, CMP, CKP, EGR, MAF and all 4 fuel injectors. All these sensors are wired to the ECU (ports 2T and 2BG) It only provides 12 Volts to the Ignition coils. As I said I checked all the inputs of the ECU (it receives 12V from Battery and Ignition) and all grounds are good also. If I take a live feed from battery and hook it to the MAF power wire the car starts and runs just fine, no DTCs at all! In fact I'm using the car hacked like this for almost a year now! :confused:
But I'm not comfortable knowing that something is wrong so that's why I want to try a new ECU to see if the car will be fixed, so that I will not need to drive a 'hacked' car ...
Any help will be appreciated! Thanks!

Maybe old topic, but to share my experience with such a car. Identical symptoms as above. P0610 which would not go away regardless of what I tried with forscan or autel.

I took the eeprom from the pcb, read it in programmer and found only rubbish data inside.

Went to scrap yard and took an old Opel Astra G dash out, and removed it's 93C56. Cleaned it and placed contents from another similar car.

Of course, mounting the ECU resulted in PATS error, which were later solved with Forscan (Autel can do this as well).

Now, the car would still not start and show all above errors.

Measuring on car, noted that there was no +12V coming out of the ecu towards many engine components, like both oxygen sensors heating elements, crankshaft and camshaft sensors, idle air control valve, EGR valve.

When looking at the ecu structure, after few good hours understood that ECU does nothing with the 12V input supplies, the pcb traces are under the plastic pins cover and run directly on the other plug. Thus mazda spared an additional wiring loom plug between chassis side and engine side.

Now, why would the traces burned out? Seems that mazda made a design error, by connecting 3 fuses of 10A in parallel, inside the ecu and sending them out. On the car found O2S1 heating element open circuited, so very likely a short in one of these burned the ecu down instead of tripping 3 fuses of 10A each. Bad bad design.

So I bypassed all traces inside ecu and now I had a fully functional car. So I thought. No errors anymore, engine started, run for 2-3 seconds and cut out. Puzzled me for 3 days. Scoped everything out, could not figure out what was wrong.

Until I realized that I had the mass air flow tube off from the throttle body, due to the work being done, and ECU did not actually had reliable MAF data, basically no air flow readout. Putting all plastic and rubber bits in order made the engine run and stay running.

Hope this helps someone.