2003 tough problem Any dealer techs HELP

[BJMarshall]

Ok here goes. This will be long. I bought a 2003 with a bad engine. Knew that going into it. I rebuilt the engine and got it back in truck. First problem, it rattles like crazy. I am unable to read rail pressure with AE so I take it to the dealer. Dealer tells me I need all new injectors. I buy new injectors and install myself. Still Rattles. I try unplugging FCA for the heck of it an no change. Guy at cummins says try a rail pressure sensor. That fixes it. Truck runs great.

Now on to real problem. I discharged AC when I removed the engine. Now that truck is running good I decide to fix AC. Pulled vacuum, charged with correct amount of refrigerant, and think I am good to go. Wrong. compressor will not come on. I can put a jumper where the relay for the ac clutch is and it kicks on and cools great. I think this one has to be pretty simple so I take it to the dealer and tell them whats going on. 2 weeks later they tell me in order to get the AC working I need to buy a new ECM and a new PCM. The tech says the PCM in the truck thinks it doesnt have ac and therefore wont engage the clutch. He says he is unable to flash it for some unknown reason.



Does any of this sound plausible? Does anyone have any suggestions?

 

[BGlidewell]

Never heard of this ECM problem before. No suggestions but encouragement seems in order. Good job so far and keep on plugging.

 

[Prairie Dog]

When ever I hear a tech claims multiple parts are needed to fix one item, my B. S. meter jumps. He want's you to by a new computer because he doesn't know how to change the settings? I'd try another dealer.

 

[sag2]

OK, it is possible you need a new PCM. Do you have any idea if it has been swapped from another truck? Yours is a DRBIII vehicle so you can't read as much data as you could if it was an 06+. Can you have a dealer read the ECM VIN from the DRBIII? It should match the VIN of the truck. On the car controllers A/C and speed control used to be learned functions, and I'm not sure on Cummins controllers.

So let's start here. Find the C108 connector. It is a 14 way connector in the engine compartment and I think it is one of the two near the dip stick. In pin two there should be a dark blue wire with an orange stripe. Disconnect the connector, and remove the terminal from the connector on the dash side. There might be a small lock you have to release before you can use a small pick tool to release the tab that holds the wire terminal in the insulator. Or if you have solder and shrink wrap you can just cut it if you can't get the terminal apart. That is the A/C clutch relay control wire from the ECM to the PDC. It should have B+ on it with the key on from the PDC. The ECM grounds it when it wants the compressor on. If you have B+ and then ground it and the compressor runs, you have just tested the control circuit as well as the load circuit. Now also if it does it may prove your need for an ECM, but without the DRBIII you can't tell for sure. It is the only way you can read if the ECM is getting the "compressor on" message from the A/C control head.

 

[BJMarshall]

Thanks man. I knew if you saw this you could direct me in the right direction. l will test this as soon as I can and get back to you. Don't think I am knocking dealers here, just wanted to give some background to the case. This tech has worked on stuff for me in the past and has done fine. I think we have a challenge on our hands here.