I have a 2000 dodge ram van 1500 with 5.2. I have recently changed plugs, cap rotor, pcv, and breather cap filter. A few weeks later it was warm out and humid and all of a sudden it died. It started fine and didn't have any issues until the next day and then it happened a couple of time and seamed to not run all that great. Few weeks later it happened again but this time had hard time starting and then a fault code came up. Replaced the AIC motor. Thought it fixed it but was wrong, the next day all hell broke loose. Ran like crap when I was able to get it to start. Took to fire stone and they stated it was the PCM. Did not replace as I heard that it could be sensors that would cause that.

So started testing sensors and found that I was getting the 5v on the reference wire but also noticed that I was getting 5v on the signal wire when the wire harness wasn't connected. So my question is, is this normal to get 5v on the signal wire when not connected to the sensor? I am getting that in all the sensors I check. Seams like I should not get that unless I have the sensor plugged in and have the condition that requires the sensor to send the signal. Am I right. Would that mean I have a bad pcm since I have the same situation on all the sensors I have tested. Anything anyone can share would be greatly appreciated.
Thanks,
John

 

Welcome to the site. I will move this thread to the second generation Ram section,
FF

 

Getting five volts on both terminals of ALL the sensors is indeed a bad thing...... Do you happen to recall what code you were getting?

 

I was getting several different codes and it seams as if the codes change everytime. I know one of them was excess voltage to the TPS for sure. It seams as if the sensors were operating properly, but with that excess voltage coming through I don't want to leave key on for any period of time as I don't want to fry out any or all sensors. If that is possible. I just thought is was unusual to be getting voltage on the signal wire when not attached.

 

Yeah, that IS a problem. Did you have all the sensors disconnected at the same time when you measured that? If so, it sounds like an internal short in the PCM. I don't have the pinouts right here handy, to see how close the wires are together in the connectors, but, it is also possible that there is just some crap/rust/whatever at the connector that is shorting them together. Wouldn't hurt to look.....

 

Upon discovering that I was getting voltage on the signal wire I disconnected the Crank sensor, the camshaft sensor, Throttle Position, and MAP snesors and was getting voltage on all the signal wires as well as the reference wire. That is what is leading me to believe that the pcm is shorted out inside. The one wire that was shorting out that I discovered was a white wire with a green stripe or tracer. When I probe that wire at the spot that was open and check on the connector for what pins show continuity it comes up with pins # 10, 14, and 25 that show continuity with the bare wire that I have taped up and covered. So my mind set is that what ever that wire controls would be what I would need to check. Having only a Haynes Manual, it doesn't go into detail for me to check. And I have not had the chance to hit the library. As stated before Firestone said that more than likely its the pcm but before I stick that kind of money into it I want to be sure. Thus all the research and checking the sensors.

 

Anything anybody can offer would be greatly appreciated. Thanks in advance.

 

The service manual is posted on this site. It is for a 2001 but will work. It has all of the diagrams. dodgeforum.com/forum/2nd-gen-ram-faqs-diys-and-how-tos/236110-factory-service-manual-for-2nd-gen-rams.html

 

Thanks Ramzy, you saved me a trip to the library and countless time looking for what I needed. I hope I can track this down and hopefully its not the pcm but alright if it is at least will figure out wtf happened.

 

I will post m findings for future people looking for answers.