DTC set by ECM vs PCM

[deehammer]

How do I tell what module the DTC is set by?  ECM or PCM?  I have a 99 so the key reading codes with the key on/off does not work.  I do have a code reader (BlueDriver)

A little background about 4 months ago it got pretty cold and I had a rough cold start which popped P0122 with a slight pedal stutter.  Cleared code chalked it up as a cold start low voltage issue.  A week or so later it did it again a couple of times.  I swapped out with a Timbo Apps and no more issues.  This morning another cold morning not too bad of a cold start no pedal issues detected however It popped P0122 again.  I am now wanting to go through the complete troubleshooting tree however I do not know if the code is set by the PCM or ECM.  I am also pretty sure that this just shows up sporadically when cold enough outside. 

 

*Update:  I am assuming, looking at the wiring diagram, that the ECM would have to throw this code so I will troubleshoot the ECM route first.  If I find nothing I will go the PCM route.  I think the chances of my Timbo APPS being defective are very low.

Edited May 17, 2017 by deehammer

[jlbayes]

Not being a smartbutt posting this. Bare with me. PCM can cause this as there is a circuit that runs to the pcm for the apps.

 

 

[Mopar1973Man]

I would read over the link that @jlbayes posted and review you electrical for the ECM to the APPS. The signal for the PCM is between the ECM and PCM but typical its the APPS to ECM.

[deehammer]

CEL has gone out like usual however the code was still showing up on my scan tool.  I cleared the code and it came back again but there is no CEL anymore.  Don't know if that has any merit on it at all being ECM vs PCM.  I will be running through the procedure when I get time soon and will update then. 

[Mopar1973Man]

18 hours ago, deehammer said:

CEL has gone out like usual however the code was still showing up on my scan tool.

Error codes will not self-erase till 40 warm up cycles have been completed without any more errors recorded.