TPS Sensor Location

[lucilu13]

Got code 122, TPS Sensor Low Voltage. First, where is the TPS sensor, and second, is checking the voltage something I can do myself or do I need to take it to a shop?

Thanks!

[BNaylor]

What size engine in your Alero?

The throttle position sensor (TPS) is located on the throttle body. It is located on the opposite side of the throttle linkage. There are two Torx T20 screws that hold it on and replacement can be done DIY. The TPS has an electrical connector where you can check the reference voltage from the PCM module (approximately 5 volts) and an output feeding back to the PCM. Idle is around .4 volts and WOT is 4.0 volts. In between the voltage should be progressive from .4v to 4.0v and linear from idle to WOT.

To get a P0122 DTC error code the low voltage side is bad which means it is under a certain threshold which is well below .4 volts.

[lucilu13]

It's the 3.4L V6. Would the issue with the low voltage also cause the engine to rev when it should be idling, sometimes over 2000 rpm? Thank you for your help.

[BNaylor]

Originally Posted by lucilu13

It's the 3.4L V6. Would the issue with the low voltage also cause the engine to rev when it should be idling, sometimes over 2000 rpm? Thank you for your help.

Yes. The PCM module (computer) uses the TPS to determine where the throttle position is to control the fuel injection system and idle. If the error code is still there then it must be corrected. A flaky idle air controller (IAC) can cause a high idle too but I would correct the TPS error code first. The IAC is located on the throttle body at the top right hand side.