dreadinger

Just bought a 1996 Chevy c1500, 5.0 4sp auto ext cab. drove it home 100 miles ran like new, the next morning it was hesitating all over and through the code P0122. I inspected and tested the wiring to the tps and all looked good. I cleaned the grounds and inspected the wiring to the ECM. It ran for about another 100 miles and started again. Cleared the code and it could go 5 miles or 50 miles but eventualy would through the code P0122 again. I repalced the Tps sensor, ran good again and then started acting up. The code it through this time was for the cam position sensor, P0340. Check all the wiring again and eventually replaced that sensor. I drove it about 100 miles again again and it started acting up again, this time it is back to code P0122. The problem is very intermittent but runs excellent otherwise. At this point it has a new fuel pump. filter injectors cleaned, new TPS and cam position sensor. Any help would be appreciated, maybe a bad ECM?

tinbender59

a few simple things check and make sure that there are no wires pinched in between the motor and bell housing ( maybe someone has had motor or trans out somewhere ) if my memory serves me PO122 is TPS High voltage. if you got a multimeter check the two outside wires on the TPS plug, Center is feedback, should be 5vdc if it is any higher you got a bad ECM, all of the sensors get their 5 volts from the ECM. could be a missing or bad ground, check that there are not loose wires arround. or could be a bad voltage regulator on the alternator, look at your voltage guage when it acts up, should not be over 14 volts!!!!

therewolf

Hi dreadinger.

Welcome to the Chevy Forums.

Take a few seconds to check the distributor. Make sure there are no cracks or carbon tracking. Be sure the rotor is up to snuff. Did the metal base of the ECM have a good coating of dielectric grease upon it?

dreadinger

Still having the same issue. I have tested all wiring and even went as far to put a volt meter in the cab and tapped into wiring. When it starts acting up the 5 volts never changes and the signal to the pcm never changes. I even tried another tps, I hate being a parts changer but I am going to try a new pcm unless someone has another suggestion.