Possible Bad ECM or Gremlins

[mhainsto]

Hello, first time posting here. I've done a lot of reading about this subject, and want to check my assumptions before I start dumping more money into parts.

 

I have a 01 Dodge 6spd 350k that ran ok until it suddenly would not start . Truck Had 1693, 1689 and 0576 Codes. Replaced the VP44 and stock lift pump with a FASS DDRP, thinking lift pump had toasted VP44. Bled the system everyway to Sunday and still could not get the truck to fire or get high pressure fuel output. Got OBDII Scanner and cleared codes, 1689 code did not return, but truck still has 1693 and 0576, I cannot get those to clear with the scan tool I have. 

 

Got sent a breakout box yesterday to test the VP44, plugged it in and got the truck to start up quite easily. After using breakout box, 1689 code returned to truck. Clear that code and plug in VP44 and truck won't start, but 1689 code does not return either. Tested VP44 plug harness with test light and have voltage at pin 7 with Ignition on, Lights up when hooked to pins 6/7 and does not light on pin 5 except after ignition is turned off. I've looked over the wiring, don't see any visible damage or issues at the plug for the VP44. I read somewhere about resetting the ECM by removing the fuse in the PDC, tried that and got the CCD message on the overhead console, put the fuse back in and the CCD message disappeared. 

 

Based on my research, it sounds likely to be the ECM, but without seeing any other codes or symptoms, I'm reluctant to replace it without ruling out other possibilities. I've also read a couple spots that the PCM can be bad causing a no start condition with the VP44. 

 

Any suggestions for additional diagnostic testing or things to consider? Thank you!

 

Edit: Wait to Start light and dash gauges all seem to work normally. 

Edited November 10, 2018 by mhainsto

[Mopar1973Man]

P0576 is cruise control voltage low error. This has something to do with steering wheel control if I'm not mistaken.

 

You can unplug the PCM and see if the truck starts. Only need the ECM for the engine to run. 

[mhainsto]

Yes @Mopar1973Man that was it! So would that mean I need a new PCM or is it possible that it needs to be reset since the replacement vp44? Where is a good source if I need a new one?

 

One more note: the key fob wont lock/unlock the doors, which might be related.

Edited November 11, 2018 by mhainsto

[mhainsto]

Solved!

I did some more reading about the PCM this morning and how the anti theft system can tell the PCM to disable the ECM to prevent someone from stealing the truck. 

So my door locks weren't working. I checked the fuse and of course it was blown. Replaced it and it blew again. I noticed the window/door switch on the drivers door was smoking and instantly remembered that having fried out months back one day when I left the window down and it rained. 

I pulled the switch, replaced the fuse and fired the truck right up...

 

Thanks @Mopar1973Man for the suggestion! I would have probably spent $$$ trying to order a new ECM and hours banging my head against the wall trying to figure it out. 

[Mopar1973Man]

No longer made. As far as u know there is no new ECM available. Just like VP44 only rebuilt units.