Still fighting the P0120 code.

[jdmidwest]

I am still fighting the P0120 error code. I replaced the TPS and the problem got worse. It started running rough and lost power last weekend while pulling the boat.

I disconnected the battery cable and let the ECM clear out. That did not work. I metered both TPS units and came in under factory spec on the resistance. Funny thing, the check engine light goes out on its own. It went off today and seemed to run fine. There must be something else causing the problem.

 

[techno]

You possibly have a problem with the electrical connections. Did you check the ECM connector voltages?

Codes will clear themselves if the problem doesn't appear again after a certain number of startup cycles, which means it might be one of those pesky intermittent issues which are difficult to trouble shoot.

 

[notrayray]

x2 on everything Techno said....

I would start very basic with the battery and ground(s) connections to make sure they are good.

Then move on to the TPS circuit.

The FSM has three possible causes...
-open or short in TPS circuit
-the TPS itself
-or the ECM.

Diagnostic procedure from the FSM
http://www.ncttora.com/fsm/1996/SIL...02rmsour/2002/024runne/di/eg5vzfe/cip0120.pdf

 

[jdmidwest]

No, I did not check the voltage coming out of the ECM. I have not experienced any other codes but I will trace the wires back and see if any bad wire.

I hope the ECM is not faulty....

 

[jdmidwest]

I think I have the P0120 error licked for now. My driveablility was getting worse with high revs and stalls and overall lack of power. I replaced the new TPS with the old stock one, cleaned the filthy throttle body and MAF sensor and it seems to be running fine now after 2 days and 80 miles. No codes and runs good.