Lightning Struck Truck!!!!

[Bwebb2119]

Well hello all,

 I don't know where to even start..... So this is a customer of ours and it was originally brought to us for no power. 1999 2500 5.9 stock. So.... Originally the truck only had throttle to 1,400 RPMS, Code was 1689, After serious going through, I diaged the ECM to be no good, Also the VP44 was bad too, Replaced VP44 and sent ECM to Auto computer performance to Andrew to repair, He was told the 1689 code and he also asked about the infamous wait to start light problem, Yes that was there too. He sent it back to me and the wait to start was repaired but still had 1689 and only 1,400 rpm. Sent it south again and he said he was pretty sure it was fixed this time, Again back into the truck and still the same code and 1 set rpm no matter where the accelerator pedal was pushed. So he sent ,e a primer gray ECM, This one now repaired the 1689, Now the truck was running properly. After a few test drives there were now PCM codes like a Xmas tree, Ungodly amount of hours in this truck and replaced the PCM (Ordered form my Dodge parts guy) Had my local PCM guy program the new PCM to this truck, All is good extensive test drives and delivered truck to customer, He puts 30 miles on it and goes into limp mode with no power, Back to our shop and I scan And find P0606; P0238; P0123; P0118; P0113; P0121. Cleared codes and 0606 stays away, Check harness again and again, Can not find any bad wires or connections, Did find the oil pressure sensor was bad, replaced and ok now, Test drive and come back and now I can NOT get rid of the P1286; P0388; P1475; They clear and come right back after some idle time, Then as I amd trying to check over I now have a P1693 which will not leave. And I also got the P0606 again but it stays off for quite a few key cycles, I am seriously pulling my hair out and i believe I may have got a poorly rebuilt ECM or something. Also in another thread I mentioned to the boys that the Black With Blue tracer wire which is the ECM sensor ground has 7.8 volts with the key on. Unplugged each sensor 1 at a time until all unplugged and it drops to 6.0 volts. Someone please have some insight for me PLEASE. Thanks in advance B Webb!!!! And also thanks for having me on this forum!!!!

[IBMobile]

Have you confirmed that it is the ECM that is letting the higher voltage into the system?  You can disconnect it from the harness and then checking the voltage at the sensors. 

[Bwebb2119]

So I unplug it from the ECM and then key on and check the ground wire on the sensors is what your saying?

 

[Mopar1973Man]

Might be worth it to just see the ECM in and have it tested and verified. 

[Bwebb2119]

It is supposed to be a new unit after he had the original one 3 different times, I am waiting for him to reply to my email and see if this is a refurbished unit or new. He said when he sent this one that it was to be a new one. 

[IBMobile]

You can check that with and ohm meter but with a volt meter check for stray voltage at the sensors from a bad wire harness.

[Bwebb2119]

Doing that now. I really appreciate the help guys.

Ok, Well ECM connector unplugged, Pin #11 is ECM Sensor ground, Ohm tested while unplugged and all sensor connectors connected to sensors, 0.0 Ohms and no stray voltage with key on, When it is plugged in I still get 7.8v on the grounds. So my wires are ok, going to have to have this computer guy UPS it back to him to verify it isn't his ECM giving me a problem; All I can hope is that is the problem

[Haggar]

B,

Sorry I didn't get online over the weekend.

 

You tested Pin 11  in reference to what?   If the ecm was disconnected and you were check ohms on Pin 11 of the harness, where did you put the other lead?  

 

I have attached the S165 splice page from the 2001 FSM.  to get any real resistance information on the wires connected to Pin 11, you would need to disconnect the ECM and ALLof these connectors at the same time.  You would then stay connected to pin 11 at the ecm connector, and probe each one of the grounds at each connector.  You would also stay connected to Pin 11 and check for continuity to the chassis, to any other system in the truck (especially battery positive).  With both ends of these wires disconnected, they should not be touching anything else in the truck.   

 

HTH,

 

I will try and watch this thread more closely!

 

Have a great day

 

Hag

 

 

2001 FSM Ram 8W-70-7.pdf

 

(edit:  it merged my threads so this was a thought a few minutes and a cup of coffee later...)

Just got to thinking, What I don't like is that you checked with the sensors connected. (or what did you actually check)  If you checked pin 11 to pin 21, you should not have read zero ohm.  you should have read the resistance of the water in fuel signal sensor.  If you checked the Pin 11 to pin 14, you should have read the resistance of the coolant temperature.  etc.

 

Also keep in mind, pin 11 sensor ground may not have a path to battery ground.  it may be a complete separate system.  you can double check this with the spare ecm.  check the pin 11 ON THE ECM to the case of the ECM for continuity.  (I am a bad lawyer, I am asking a question that I do not already know the answer to.  I have not checked this out.)  But I suspect that sensor ground and truck chassis ground have nothing to do with each other.

 

Hag

Edited April 15, 2019 by Haggar
merged threads