Hoping someone can help me trouble shoot a TPS problem throwing a Code 22 continually. The truck suddenly began not idling properly, then missing when accelerating, so it barely runs at times. If I let it warm up, sometimes, it gets better so I can move the truck. Other times it will idle until warm, then it dies. In addition to the Code 22, I had a code for bad Engine Coolant Sensor, which I replaced and the coolant sensor code went away, but problem of running poorly persists as does the Code 22.

I checked voltage at TPS and ground is good as is the power in. The middle wire does have very low voltage and does not fluctuate when throttle is moved open. The middle blue wire back to ECM does have continuity to ECM and I checked that there is no continuity registering to ground. I also cleaned the obvious ground I see at front of block, but have good ground at TPS ground wire.

Here's what I have done once the problem began, each time I swapped out a part, the problem persists:
New MAF
New TPS (non-adjustable) and result was same on both old and new TPS
New (rebuilt ECM)

I have not checked IAC or EGR because that is not related to the low voltage at middle wire of TPS/ECM wire. Is there something at (new and old ) ECM that would cause low power?

Any ideas would be helpful, it is my plow truck and I am getting nervous I will be shoveling my 1/4 driveway!

 

No MAF sensor on a TBI truck.

As for the TPS code 22, check the +5 volt power going to the TPS. The connector or terminal could be bad. It should be the gray wire going to connector position C.

Note that the +5 volt power is shared with the MAP sensor. Since there isn't a MAP low code the ECM is most likely providing the proper 5 volts.

RBob.

 

Thanks RBob, Yes, my bad on the MAF/MAP confusion, thanks.

I will try checking tomorrow once the weather warms up a bit - great idea, thank you!

 

So, its been pretty cold and am working outside so I waited for it to warm up a bit. I swapped the TPS plug today and problem persists. I confirmed by pulling battery cables, waiting and checking that code 22 was gone. Re-started and code 22 returned and truck was loping under partial throttle and not idling great after warming up. Any other thoughts?

Thanks!

 

Did you check the 5v ref and blue feedback wire ?

 

 

Thanks - this is helpful. In reply, yes, before swapping TPS and plug, I had good ground and proper voltage. I did confirm the blue wire had low voltage and still does. And, thus, re-triggered the code 22 after re-set.

 

If the tps is adjustable feedback voltage should be .54-76 vdc. I think more towards the .54 range and close to 4.5-5v wot.

 

Yep, but I have the non-adjustable version. All I can think of is to re-check the three wires again. Everything checked out before, except the blue wire and I found continuity to ECM.

 

http://chevythunder.com/tps_code_22.htm

Bad ecm maybe ?