TPS Voltage Check Question

[splitz]

I'm doing some troubleshooting on the 97 XJ automatically unlocking the TC and even downshifting sometimes.

Instead of boring you will all of the details, I figured I'd keep this post to one question:

Does the Jeep need to be at operating temperature to do the checks?

Everything is good EXCEPT the critical PIN 2. When the Jeep is cold and throttle is closed, I get 4.66 volts. That's right 4.66. The voltage does not change when the throttle is opened.

According to this test guide (I am a certified Internet mechanic afterall), the voltage should be .4-9 when closed and sweeping 3.5 to 4.5 based on the throttle's position. Clearly mine is not within spec.

 

[Tim_MN]

I prefer the specs below. Heat may cause a weak or faulty TPS to read further out of spec.


The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. This will vary in an approximate range of from .25 volts at minimum throttle opening (idle), to 4.8 volts at WOT wide open throttle.

 

[Unclewolverine]

Short answer is no. Cold or hot doesn't matter. If you have washed the engine recently you can count the tps good as fried though. Ive fried several that way. Last one I slathered in silicone around that seam on the outside before installation and haven't had a problem since.

 

[splitz]

This will vary in an approximate range of from .25 volts at minimum throttle opening (idle), to 4.8 volts at WOT wide open throttle.

Since I'm getting 4.6 minimum on Pin 2 (to PCM), I'm going to guess my TPS is shot.

Short answer is no. Cold or hot doesn't matter.

Thanks for the quick and short answer!

If you have washed the engine recently ...

Washed the engine? Ain't nobody got time for dat

 

[Unclewolverine]

Lol!

 

[lawsoncl]

Check that you have a good ground too. If the ground wire isn't connected, the signal pin will be at the same voltage as the +5volt pin.