4L80e Code: 22 - Throttle Position Sensor low voltage

[SmartDrug]

Took out the HMMWV for the 4th of July and all systems seemed fine, but it hung 1st gear until much higher in the RPMs (20+ mph 1-2 shift at mild throttle) and was a pretty rough shift when it finally did shift. Seemed to run through the gears, but all seemed late/rough, not stuck in 2nd/Limp, no trans light showing. This happened once before (last winter), but it stopped happening on its own and I hadn’t seen it since.

The kicker here is that I tore my dominant arm distal biceps tendon later that evening and just had surgery, so I haven’t had the time to diagnose aside from sitting in bed on pain meds worrying.

Any idea where I should be looking aside from the transmission reset button? Anyone experienced this before? I couldn’t find any related older threads.

 

[Mogman]

Have you read the codes? not all turn on the trans light.

 

[SmartDrug]

Have you read the codes? not all turn on the trans light.

I did not realize that, I’ll check it out, thank you!

 

[SmartDrug]

Code 22 Throttle Position (TP) Sensor circuit low is the only one showing. Thanks for pointing out that the light might not illuminate, didn't consider that.

 

[Mogman]

Just in case you don't have it.

 

[Retiredwarhorses]

Code 22 Throttle Position (TP) Sensor circuit low is the only one showing. Thanks for pointing out that the light might not illuminate, didn't consider that.

no “trans” lamp? That means you aren’t seeing the TCM, so could be anything from CB tripped, power connection to TCM, even a defective TCM.
Now your in limp mode…I would not drive it till you have identified the issue.

 

[NDT]

The TP sensor is simply a rheostat that increases or decreases voltage based on how far you have the pedal pressed. That voltage is what the computer reads to judge when you want shifts to happen. Right now it’s thinking you want max power high rpm shifts as it is not reading correctly. Check the tps and wiring.

 

[SmartDrug]

no “trans” lamp? That means you aren’t seeing the TCM, so could be anything from CB tripped, power connection to TCM, even a defective TCM.
Now your in limp mode…I would not drive it till you have identified the issue.

The Trans light comes on when power is turned on, but turns out after a few seconds. No flashing/illumination beyond that, until it's put into the code read mode, then only Code 22. Its shifting through the gears albeit roughly as @NDT pointed out, as if I were driving at full throttle. Thus far the wiring looks intact, but I'm unable to do any real diagnosing, checking voltage, etc. until my arm heals up a bit more.

I haven't dug into the TM for this yet, is calibrating a TPS a bother on this or is it a basic .45v-4.5v sweep?

Thanks all for the replies!

 

[Mogman]

The Trans light comes on when power is turned on, but turns out after a few seconds. No flashing/illumination beyond that, until it's put into the code read mode, then only Code 22. Its shifting through the gears albeit roughly as @NDT pointed out, as if I were driving at full throttle. Thus far the wiring looks intact, but I'm unable to do any real diagnosing, checking voltage, etc. until my arm heals up a bit more.

I haven't dug into the TM for this yet, is calibrating a TPS a bother on this or is it a basic .45v-4.5v sweep?

Thanks all for the replies!

 

[SmartDrug]

Little update-

Arm finally up to the task of letting me climb on the front wheels, so I could inspect the TPS. It had a bit of corrosion, which I cleaned up, voltage tested good, slapped on some dialectic grease and everything was back to normal. Shifts smoothly, rides great.

When I first got her, I went through the electrical stuff and cleaned/greased most contacts, I guess this one slipped by me.

Anyway, I appreciate the help!