TPS low voltage code makes torque converter not lockup?

96 Sonoma Zr2 4x4, 4.3, automatic (4l60e).
The symptom is the torque converter doesnt lock up. So my drive on the freeway is at too high an rpm, and I assume working the tranny too hard. (not good for it)

The code that pops up is for low voltage to TPS. My cold idle also fluxuates up and down, but there is no code that seems to point to why. My main concern is the torque converter not locking up.

New EGR, new oil pressure sender, good fuel pressure, tranny checks out fine, It is a fairly new AC delco TPS. The TPS itself was put in at a shop, and they checked the "sweep" and the voltages were good at that time.

What seems like a coincidence, but not: idling for a while seems to be what sets off this TPS low voltage code??

yup. that code will do that, and it can also cause your fluctuating idle if the readings are bad enough. Recheck the the voltage sweep. A volt meter and a good wiring diagram will help you out. also, if possible, check it with a scan tool with datalogging capability to see what the ecm is seeing. may just need to unplug and plug the tps in a couple times, could just be a dirty/loose contacts giving a false reading.

Had this same issue on a 3800 swap I did a few years back. Bad TPS was the cause...Swapped it out and all was good..

quote Originally posted by GreenPlatypus: yup. that code will do that, and it can also cause your fluctuating idle if the readings are bad enough. Recheck the the voltage sweep. A volt meter and a good wiring diagram will help you out. also, if possible, check it with a scan tool with datalogging capability to see what the ecm is seeing. may just need to unplug and plug the tps in a couple times, could just be a dirty/loose contacts giving a false reading.

I will for sure clean those contacts and give her a try first. Free fix if it works. Need to disconnect the neg battery cable while or after cleaning?

quote Originally posted by 2.5: I will for sure clean those contacts and give her a try first. Free fix if it works. Need to disconnect the neg battery cable while or after cleaning?

No need to disconnect the battery. Just make sure the ignition is off.

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