PROBELM WITH FREIGHTLINER TRUCK-CLASS 8

**mathura** · 10th August, 2013, 04:38 PM

I hooked the Freightliner service link to a freightliner tanker yesterday and found fault code with the ICU module- icu140 spi 168 fmi 1.( low voltage detected at ICU(instrument cluster unit). However I tested the voltage before cranking 12.7V while cranking 10.5V after cranking 12.6V.

The engine is not starting but when I hooked insite I found no faults detected in ecm

My question can this fault code prevent the engine from not starting

ANYONE WITH AN ELECTRICAL SCHEMATIC FOR THIS TRUCK

Thanks

**Schoolbus Tech** · 11th August, 2013, 02:36 AM

Try this if see if you can access this https://secure.freightliner.com/acce...08SD-114SD.pdf I think I have it somewhere zipped up . Just thought this would be quicker for you Need to know what engine and what yr please I have lots of MBE and cummins diagrams ICU 3 diagrams https://secure.freightliner.com/acce...=030Instrument I you need more things for future reference https://secure.freightliner.com/acce...sp?page=wiring

**Schoolbus Tech** · 11th August, 2013, 03:18 AM

This has a lot in this for the ICU4. Hope this helps just PM me if you need more . I don't think a problem in the ICU will keep it from starting but the problems might be linked . You have checked ignition fuses . Just cause the fuses is not blown does not mean voltage is flowing darn cheap plastic PDM modules when they get hot and worn the fuse sockets spread apart . Had 3 months ago would stall and sometimes not start 4 people before me looked at it over a period of 2 months I was messing with the ignition switch got it to screwup and it worked everytime afterwards so I played with the switch again and it screwed up again replaced it seems to be working great .

**mathura** · 11th August, 2013, 01:11 PM

Thanks Schoolbus Tech

It is a 2010 model non-Cascadia Freightliner Truck with Cummins ISM engine, I had written down the vin but right now I cannot locate where I left that piece of paper.
I feel that the fault code 140 168 could not prevent the engine from starting because I have tested voltage at engine ecm while cranking and I am getting 10.5V, however this truck is under warranty and the owners would not allow me to do what I want.

The are talking with the Freight liner representatives and as such only what they instruct I can do. When I questioned the rep why the fault count(2147 times) is so high for this fault he did not give me a straight answer. he said we probably were trying to start the engine that many times. I told him that this truck was working with this fault existing

**hercamp** · 11th August, 2013, 04:47 PM

i have same problem with couple of them, you can try a little test i do while the engine is cracking ,shake the key . i had to replace the key switch in 2 of them .maybe this can help you.

**mathura** · 12th August, 2013, 01:24 AM

Originally Posted by hercamp

i have same problem with couple of them, you can try a little test i do while the engine is cracking ,shake the key . i had to replace the key switch in 2 of them .maybe this can help you.

Very unusual but I think I will try what you experienced

Thanks

**Roy Suryadwiananda** · 12th August, 2013, 03:52 AM

Maybe the Batteray Terminals loose, can cause low voltage or there is a problem with the fuses ?, also check the Starter Relay Coil resistant.

**Schoolbus Tech** · 13th August, 2013, 12:17 AM

Hey mathura let us know what you find .

**hercamp** · 14th August, 2013, 05:57 AM

this week one of them on shop. ign relay fail , and mayke it not start . try to check the ignition v , on ecm and the supply from ign relay.

**RAULIN** · 14th August, 2013, 09:41 AM

hi guys by the pdm inside of cab is 2 power relay they are biger than the rest one is for the ignition and the other is starter they go bad a lot,check on fuel pump the fuel shut of solenoid for 12 volt they go in short to.

**mathura** · 1st September, 2013, 01:59 PM

UPDATE
The Freightliner agent came to work on the truck and after working on it a whole day they could not clear the code, so they requested that I attend the job in their presence, with insite software.

They wanted me to check the power points on the engine ecm which I did and they were convinced that it was not a power issue with the engine.
After I hooked insite and started data monitor I realized that engine was not seeing cranking RPM. I then checked resistance of engine position sensor and it was within specs.
I decided to remove it and discovered it was damaged at the tip, replaced sensor and engine stared.

The Freightliner agent then told the company officials that I have their permission to work on these trucks anytime while under warranty.

**mathura** · 1st September, 2013, 02:02 PM

UPDATE
The Freightliner agent came to work on the truck and after working on it a whole day they could not clear the code or get the engine to run so they requested that I attend the job in their presence, with insite software.

They wanted me to check the power points on the engine ecm which I did and they were convinced that it was not a power issue with the engine.
After I hooked insite and started data monitor I realized that engine was not seeing cranking RPM. I then checked resistance of engine position sensor and it was within specs.
I decided to remove it and discovered it was damaged at the tip, replaced sensor and engine stared.

The Freightliner agent then told the company officials that I have their permission to work on these trucks anytime while under warranty.