schiker
Well-Known Member
Brother in laws truck. 04 dodge 1500 PU, 3.7 v6 gasser.
He is getting intermittent high idle issues (normal idle is ~700 issues it fast idles to 1100 rpm sometimes) and one random stall. Otherwise runs ~ok. Check engine light comes on and go off at various times.
I used code reader and found p0122 throttle position sensor circuit A low voltage.
I looked and its a mechanical linkage pedal and I see 2 electrical plugs on intake body opposite side of intake from cable mechanism I guess to the butterfly in intake.
I pulled plugs and they look pretty clean. I sprayed them with contact cleaner and blew out with compressed air hose and then connected them back up and wiggled them around some.
I read somewhere ref 5 volts on one pin, ground, and 3rd wire/pin goes to ecm: range 1.7-xx volts???. How would I test this exactly? Check pins on harness continuity to ground and look for 5v on another wire 3rd wire would be to ecm with key on "run". I have a regular mid quality DMM with regular probes. What is easiest way to test the ref voltage signal to ecm? Its a little cramped to try and back probe it and never really done this either.
I am thinking next time I might try to stick a straight pin in back of plug then aligator clip a wire lead to it then to my DMM probe end. Will that be accurate enough I assume all I am looking for is a smooth voltage climb from ~1.7? at idle to about 4.5 volts at max throttle position. Does the truck have to be on and running or just key on "run"?
I think I have heard stuff about the gas cap not sealing correctly causing issues with this??? Any likelyhood of this or other issue causing random problem.
He is getting intermittent high idle issues (normal idle is ~700 issues it fast idles to 1100 rpm sometimes) and one random stall. Otherwise runs ~ok. Check engine light comes on and go off at various times.
I used code reader and found p0122 throttle position sensor circuit A low voltage.
I looked and its a mechanical linkage pedal and I see 2 electrical plugs on intake body opposite side of intake from cable mechanism I guess to the butterfly in intake.
I pulled plugs and they look pretty clean. I sprayed them with contact cleaner and blew out with compressed air hose and then connected them back up and wiggled them around some.
I read somewhere ref 5 volts on one pin, ground, and 3rd wire/pin goes to ecm: range 1.7-xx volts???. How would I test this exactly? Check pins on harness continuity to ground and look for 5v on another wire 3rd wire would be to ecm with key on "run". I have a regular mid quality DMM with regular probes. What is easiest way to test the ref voltage signal to ecm? Its a little cramped to try and back probe it and never really done this either.
I am thinking next time I might try to stick a straight pin in back of plug then aligator clip a wire lead to it then to my DMM probe end. Will that be accurate enough I assume all I am looking for is a smooth voltage climb from ~1.7? at idle to about 4.5 volts at max throttle position. Does the truck have to be on and running or just key on "run"?
I think I have heard stuff about the gas cap not sealing correctly causing issues with this??? Any likelyhood of this or other issue causing random problem.
