My 2002 Ram 1500 5.9L is having an issue where it will not start. Recently acquired the truck; when I got it, the security LED would flash and not start. I replaced the battery and the truck started right up. I had it running at idle for half an hour then took it around the block and it died. I was able to restart it and get it home, but it died again as soon as I pulled up to the house and I have not been successful in starting it since.

Here is the current state of the truck:

• The truck will crank, but not start.
• When I turn the key on, the Security LED performs the self test and then stays on solid. (with both keys, gray head)
• Brake, ABS, Check Engine, and Fuel Light stay on. Fuel gauge and voltage gauge do not work.
• Battery is new and fully charged.
• Unsuccessful to get an OBD connection using a couple of cheap scanners. Units power up, but can never detect the correct protocol.
• Unable to get any DTCs to display by the 3x OFF/ON ignition procedure.
• Borrowed a Foxwell Automaster Pro scanner.
  • The OBD function does never detects the protocol and does not connect.
  • The SCAN function allows me to manually select year/make and I am able to connect to various modules
    • SKM - SKIM/SKEEM/TPM reports two faults: "Serial Link\External Failure (P0000C0)" and "PCM Status\Failure (P0000C0)
    • MIC/CCN - Mechanical Instrument Cluster has one fault: "PCM Messages\Not Received"
    • ABS - One fault: "Code 84 Mismatched\Vin (P0080)"
• Tested all fuses near battery with multimeter, all were OK.

At this point I am at a loss on what my next steps should be to pinpoint the issue. I've found a few posts where the fix was replacing the PCM, but also found as many where that was not the issue and I'd like to eliminate everything else before ordering a replacement. Does anyone have any insight into this issue or what my next steps should be? Is there anything I can test on the PCM side to help isolate if this is a PCM or wiring issue?

Also, I am not sure if this is of any importance, but today while I was turning the ignition OFF/ON to try to get the DTCs to show, at one point the security LED started flashing. I got hopeful and thought that this was a sign that the PCM and SKIM was communicating again so I disconnected the battery, held the positive and negative terminals together for several seconds and reconnected the battery. When I turned the ignition back on, the security LED went back to solid red.

 

Apparently, someone already replaced the PCM once, and did not flash it to the correct VIN. Either that, or the PCM is indeed having issues, and has some corrupted data.

 

According to a forum I post I came across it looks like it's also possible that if the ABS module was replaced by a used one, that code would be thrown. If the PCM was swapped without a VIN change would I see similar codes in any of the other modules?

 

Do you have any history on the truck?

 

Not much, unfortunately. Guy claimed he had it for about a year, used it as a daily driver. One day it wouldn't start so he had it towed home and ended up replacing the fuel pump. He said it ran fine for a couple of weeks and then the truck wouldn't start and the security LED would flash. That seemed to be a pretty common indicator of a battery issue so when I got it I put a new battery in it and then it started right up. While I had it running, there was no CEL on and everything seemed fine. All the dash lights didn't come on until after it died on me the 2nd time.

 

Might try disconnecting the battery for an hour, and see if anything changes..

 

I'll give it a shot.

Update: Reconnected battery, no change.

 

I don't know what the procedure is to reset the security, or have it learn a new key..... which I suspect you may need to do. Service manual should have that info.... but, I bet you need a chrysler scanner to do it as well...

 

Did you ever resolve this? Got a truck doing the same thing and am trying to figure it out.

 

Yes I did. Somewhere on the internet I found a thread about someone having the same issue because of a failed sensor. I think it was either one on the throttle body or crank position sensor. Mine ended up being a crank position sensor, but I changed both.

It's been a while, but I think the theory was the sensor was failing and internally shorting the 5v? Rail in the PCM which was causing it to do all kinds of odd things.