1997 dodge dakota p0123

QuestionEdit

QUESTION: Roland, I have asked a few questions on this before and have still not figured it out.. I even gave in and took it to a shop again they failed. I have determined that the tps voltage is actually good but the computer is reading it as if it was at wide open throttle the backprobe results show voltage getting to the computer at idle at .95v and acceleration equals a greater value all I can think is somehow something is lying to the computer the question is what... I have not determined why the cruise control is dead either and really think there is a connection in that somehow but I hate quitting I will find it but I am hoping you may have come up with some other ideas in the mean time. I know I am over looking it or dismissing it as irrelevant. I need another idea from you if you have any left... Let me know much appreciated.

ANSWER: Hi Guy, About all I came up with was a short between the cruise control wire and the tps sensor wire which I thought might be adjacent to one another at the plug if the pcm is wired as it is for the van of that same year. I recall you said that you had replaced the pcm so it can't be that. Do you have the wiring diagrams for the Dakota? Voltages just don't come up wrong without an explanation. 0.95V doesn't sound right at closed throttle. I would almost be willing, if it were my vehicle, to 'open' the sensor signal lead of the tps and observe whether when so-disconnected from the harness it shows a varying voltage in the proper range of values (should go from close to 0V when closed, to close to 5V at wide open as you move it through the full range of motion) or not. If it did, then I would splice in a new signal wire between the sensor and its pin at the pcm plug. Also, before doing that be sure to verify that there is 5V the violet/white wire, and that the black/light blue ground wire isn't being shorted to some stray voltage between the sensor and pin 43. Roland

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QUESTION: I did try the sensor wire replacement before and to no avail. When I disconnect the sensor wires it reverts to wide open throttle which from what I gather is normal. I have checked for any stray voltage on the ground circuit and its good. .95v is a little high at idle .70v is "normal" I have the voltage coming in at the correct amount roughly but IDK what happens after the computer gets it, I am seeing high voltage at tps on the scanner. IDK what other factors are in that wiring to the obd plug. I can only think something else is causing this reading and subsequently causing the running and shifting issues. Let me know what else you think of if anything this is insane how weird it is...

ANSWER: When the key is in the run position, but the engine not running, do you see the sensor signal vary smoothly from 0 to 5v when you open throttle wide, using a voltmeter? Do you see it similarly at the pcm pin for the wire? That is all you need to know whether it is correct.

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QUESTION: It's never at 0 lowest is .95v but it does increase and decrease smoothly with acceleration. The tps is actually working according to what I can find which means I will never fix it looking at the tps. The PCM pin shows the same voltage as the tps reads. Any ideas where to go from here?

AnswerEdit

I wonder what is the symptom/malfunction that you are trying to deal with? Maybe set aside the tps code and think about what else could produce the symptom. While again I don't have the troubleshoot manual for the truck engine, I do believe that the voltage should go to zero at one end of its range of motion, not to so high a 0.95, but that could be different for that engine but I don't see why.