Archived 07. 6.7 3500 c&c PCM shut down engine and locked out starter.

[mwflyer]

Truck has been down two weeks , no one so far has been able to repair. PCM won't communicate is it likely that it needs new PCM?

 

[cerberusiam]

Either that or a security lockout has been activated, possibly the ECU lost the VIN and may just need a reflash. Hard to tell unless it is at a delaer or shop with the right equipment.

 

[mwflyer]

The dealer reset the IOD fuse says the security sys. Is not the problem. The service manager says the PCM won't communicate. Their solution is to start with 3500. 00 PCM and other module replacement with no expectations that it will resolve the problem.

 

[sag2]

Any module on the truck needs only powers, grounds, and BUS wires to communicate. Cummins controllers are very robust, and short of jumping them backwards they hardly ever fail. Do you know anyone with a 07-09 vintage truck that could be used as a test truck? Install your ECM on the good truck and have the dealer attempt to communicate with it. If it talks to it you have a wiring problem, if not a bad ECM. Might be less expensive to waste a couple hundred that way than $3500 for a new ECM.

 

[Joseph Donnelly]

I don't know where you are, but if the truck gets parked in semi-rural areas, check for rodential munch marks on the wires!

 

[Joseph Donnelly]

I don't know where you are, but if the truck gets parked in semi-rural areas, check for rodential munch marks on the wires!

 

[mwflyer]

Thanks for the help gentlemen I really appreciate the response. I am located in Spanish fork. Utah. The truck is at an independent mech, who was the dodge cummins guy at our local dealer where I purchased the truck before they were closed by the factory. I think that he is looking at the wiring throughout all the sensors on the engine. Do you think a short in the flatbed wiring could cause the problem. There was one 40amp fuse blown that goes to the rear of the truck, when we changed that fuse it didn't blow again. Thanks again. .

 

[Joseph Donnelly]

A blown 40 amp fuse is a "wake-up call!" The short may be intermittent so check those hot wires for worn insulation, or rodent chewing.

 

[mwflyer]

Do you think a short in the wiring behind the cab or engine compartment could cause this kind of problem with the PCM?

 

[cerberusiam]

Do you think a short in the wiring behind the cab or engine compartment could cause this kind of problem with the PCM?

If you blew a 40 amp fuse to the flatbed you might have blown the ECU and or TIPM as well. The whole system on these trucks such if it isn't run thru relays as it can and will take down the controllers, aka computers.

Without some expensive test equipment it is almost impossible to tell if the ECU is bad, other than nothing works. The ECU will self protect from a short in some circuits so you migh start disconnecting all the circuits to see if that will help.

 

[sag2]

Is the shop using a Chrysler scan tool or a generic scan tool on the truck? Chrysler uses a different communication system than the generic tools do. If using a Chrysler tool, can they talk to any other modules on the truck, especially the TIPM? If not then the entire Can C BUS is down. If they can talk to other modules then focus your attention only on the ECM.
On the C2 60 way connector at the ECM you need power on pins 45, 49, 50, and 60. You need grounds on pins 47, 48, and 57. You need to measure the BUS voltage on pins 1 and 21.

 

[mwflyer]

I don't think he is using a Chrysler tool I do remember him saying that there was one place in the scan process that was a language that all vehicles respond to. It started with J and a series of numbers I don't remember.

 

[Sticks]

He's close, there are three basic protocols ISO, SAE and KWP, then those get broken down into sub groups.



ISO 15765-4, ISO 14230 KWP2000, ISO 15765, SAE-J2284, SAE-J1850 PWM and VPW.



Some high end universal scanners (Snap On, OTC... ) can almost read/communicate with all the computers on a vehicle, but more often than not, you need the manufacturer scan tool, in this case the DRB.



His scanner may see the module, but can not communicate with it.



For what our shop paid for a Snap On scanner, they could have bought a DRB, Star, and Tech scanner for the big 3 US manufacturers.

 

[DieselLady]

At one time I had an 06 dodge in my shop that would crank, but had no communication with the ECM, or PCM. It took a while, but we found the wire that was not providing power on startup. It ran through the big connector at the firewall above the rail. Dang was I pulling my hair out. But we finally found the problem. You should have him ring out all the power and ground wires that run to the ECM/ PCM and make sure it has the proper connections.
I agree with sag2. These controllers don't fail that often. So before you allow him to spend the money, make sure he has done the work to prove it is bad. ")

 

[mwflyer]

Would that wire you are talking about be in the same location on the 6. 7 engine? I think he spent most of this past week checking wire connections or doing a pin out test was the term he used. It is still not up and running. Thanks for your input.

 

[DieselLady]

Yes it was switched ignition wire that ran through the big connector above the rail on the top of the firewall.