mopar dude

i have OHM tested the circuits and everything tests good< the black and blue wire that the sensors use for ground goes everywhere i cannot find a schematic of where it goes after the engine harness ? Do u know if the grid heaters should cycle on and off when the engine is running for the first few minutes ? thanks for your time. Do u think the p0606 code is cos of a short or bad ground too

Ok. I performed the W-T ground reference modification this weekend. I inspected and tested every wire on the engine harness. Everything looks and tests good. I then reinstalled engine harness. Started the truck, it ran ok for a few minutes, then check engine light came on: P0123. Both coolant and intake IAT, both went to -40. Tried to turn the truck off but engine kept running with ignition off. Removed fuel pump relay and that is when the engine shut off. Swapped relay, started the truck and it did the same thing (engine would not shut off with ignition). I cleared check engine light, started the truck next day (today), truck ran fine for approximately 10 minutes, then threw P0123 & codes for air temperature sensor, coolant temperature sensor, and P0606 ECM processor. Also, not sure if this is normal, but I did notice that grid heaters cycle on and off for first 5 minutes of engine running. Any more ideas are appreciated. Thanks!

I will recheck the engine wiring harness this weekend, i have had the ECM checked by ACS and they said ECM is good no fault found, maybe i should just look for a new ECM.

I finally had time to start the truck yesterday morning. It was 32F outside. Started the truck and let it warm up 10 minutes. Truck ran ok. Looked at live data: ECT was 108F, IAT was 100F. I backed up the truck, put in 1st gear and went to accelerate, then check engine light came on. Engine started surging. I looked at live data and the ECT & IAT were -40F for about a minute or so. The code P0123 appeared.

Hi John, I have not heard of the W-T ground reference modification? But I'll check that out tonight. I did start the truck when I got home tonight a few times, and the engine shut off with the key. I hope to work on the truck more on Sunday. I did notice, when I went to start it the first time when I got home, the temp gauge went to hot and the dash flashed p0121 and p1693. This is the first time I have noticed the dash flashing the codes up. After about 1or 2 minutes, the temp gauge dropped back down. When the temp gauge does this, that's when it sets a code and I have a dead gas peddle. Thanks again for sticking with me. Appreciate it.

Thank you for responding. Below are the answers to the questions. Please ask more if more clarification is needed. I appreciate the help. P0121 - Accelerator Pedal Position Sensor Signal Volts Do Not Agree w/Idle Validation Signal P0123 - Accelerator Pedal Position Sensor Signal Voltage Too High Any history on how many miles or age on the APPS? - I forgot to put that I have replaced the APPS also. Need more detail here. Does this happen immediately when the key is turn on or when the engine is started? - The issue is intermittent and happens when the key is turned on and engine is running. What is "hot"? - 200°...., 220°?..., pegged? - The needle pegs to max. Are any other gauges being affected when this happens? - No other gauges are being affected. Only temp gauge. Does this happen every time? - No, this happens intermittently How are you shutting the engine off when it does happen? - I have to put the truck in gear and stall it in order to turn it off. Please give more detail about the history of your truck (ownership, miles, problems, etc). I've owned the truck for over 10 years with no issues. Truck has 320k+ miles, ran good until this started happening last November. Did the 3 listed issues just start all at once , or come on gradually and separately? These issues came on all at once a few months back. Over time, the intermittent frequency has increased and gotten worse. How well does the engine run as far as performance on the road? - Truck has plenty of power apart from when these intermittent issues occur.

Hello everyone, I have a 2002 Dodge Ram 3500 24v manual that has an issue I can't seem to figure out. Hoping y'all can help a brother out. It has the following issues: 2 codes randomly: P0121 & P0123 Temperature gauge goes to hot The engine won't shut off with the ignition key. The following troubleshooting has been done: Checked engine wiring harness - no faults found. Had the PCM and ECM checked by 3rd party companies - no faults found Replaced injection pump Replaced alternator Replaced ignition switch Please feel free to ask me any questions. But really looking for some help as I'm at a loss of where to check next. Thanks!