More ECM troubles. ECM & PCM how are they integrated?

[GShail]

I thought I had things figured out with my truck but I am back to where I started it seems. If you have read my previous threads about the ECM you know that I tried a salvage ECM that I was able to get working with a SMARTY recovery program. The truck worked and ran fine all the way to California and back towing three cars, went over 1,800 miles with no problems. Today I got about a mile from my shop when the same 2146 code as well as corresponding 201,201, and 203 codes showed up after I pulled over because of no power and knocking. These are the very same codes I had been dealing with last week.



I am having trouble believing that the salvage ECM is the culprit. The truck is doing a couple of strange things. First strange thing is that the backup lights come on even if the truck is off, . . . so long as the gear selector is in reverse. Addittionally, the AC light will come on when the truck is off if it is depressed.



How are the ECM and the PCM integrated? Could problems with the PCM be affecting my ECM?

 

[Triton]

I thought I had things figured out with my truck but I am back to where I started it seems. If you have read my previous threads about the ECM you know that I tried a salvage ECM that I was able to get working with a SMARTY recovery program. The truck worked and ran fine all the way to California and back towing three cars, went over 1,800 miles with no problems. Today I got about a mile from my shop when the same 2146 code as well as corresponding 201,201, and 203 codes showed up after I pulled over because of no power and knocking. These are the very same codes I had been dealing with last week.



I am having trouble believing that the salvage ECM is the culprit. The truck is doing a couple of strange things. First strange thing is that the backup lights come on even if the truck is off, . . . so long as the gear selector is in reverse. Addittionally, the AC light will come on when the truck is off if it is depressed.



How are the ECM and the PCM integrated? Could problems with the PCM be affecting my ECM?

Maybe this will help you understand something... PCM



It does sound as if you have wiring/ECM issue. Have you loosened any ground wires that didn't go back tight ?



Good luck

 

[GShail]

There are no codes indicating a PCM problem but why are the backup lights coming on when the truck is off and in reverse gear? why does the AC light come on when the truck is off?



The ground wires are tight.

 

[Triton]

I wouldn't think you'd have any PCM codes with the issues you're having. That would be in the ECM. I just thought you might want to read about the PCM. I don't know how they're integrated... but, they are.



All I can suggest is to get the truck on a Starscan to see what's going on. You obviously have voltage flowing when it shouldn't be.

 

[LMcCary]

Check the ignition switch.

 

[GShail]

Ignition switch, hm m m m m . . . had not considered that but will delve into it.

When the truck was at Industrial Injection last week we ohm'd everything out and it kept showing a failure on the high side driver cylinders 1, 2 and 3.

 

[Marco]

Got the problem figured out? Any news?

Marco

 

[RMalone]

I thought the ecm and pcm were integrated on the 3rd gen trucks??

 

[PBrauer]

I think you need to check the wiring to those gauges (from the other thread). Sounds like the power to one of them is interfering with your ignition switch. Didn't you say that one stays on when the others are off?



The "ghosts" you mentioned in the other thread might seem trivial but anything that messes with the SKIM (or whatever they're calling the security key transponder nowdays) can cause some really unusual and hard to explain/find problems. I'd unplug that Quadzilla then see if any of your ghosts go away. If they do then you might just be tapping the wrong wire.

 

[rbattelle]

Manual transmission trucks don't have a PCM - only automatic trucks have a PCM (at least up until the TIPM came into use).



Ryan