1997 Regal TPS Malfunction

[magnoliablossom]

I have a beautiful 1997 Regal GS 3.8L Supercharger (I love saying that ). Anyway she has about 130,000 miles on her and recently she has started turning off whenever I press the brake. When I shift the car in neutral before applying the break she does just fine. Anyway, I took her to Advanced Auto and they did some kind of computer scan on her to see what the problem was. This is exactly what the printout says:

Vehicle Scanned
1997 Regal
1=3.8L

Set DTCs (codes)

History DTC P0121
TPS/Pedal Position
Sensor A
CKT Range/Perf
MIL REQUESTED
Since IGN NOT RUN
Since Clear P/F


These codes indicate a malfunction in certain systems or components. Proper diagnosis should performed by a mechanic or through proper diagnostics ounlined in the service manual for your vehicle.


Now the guy at AA told me that if I had that sensor replaced that would fix it. But a friend of mine told me today that just because AA's computer said that was the problem doesn't mean it is.

No worries people...I'm not the one going to be making the repairs and I'm not going to bog you down with a bunch of "but" questions. I'm going to print out your replies and show it to my friend and he'll do it for me. So, please, any suggestions would be appreciated.

Thank you,
Magnolia

[BNaylor]

Welcome to AF.

I would take the P0121 DTC at face value. It indicates the TPS has a circuit range/performance/rationality fault. In a nutshell it indicates the TPS is sticking. The PCM module looks at the last throttle position value to see if it is greater than or less than the predicted throttle position. If off or out of range the DTC will set and trigger the SES/CEL Mil light.

On a TPS at the electrical connector and pressing the accelerator you can check the PCM 5 volt reference signal at the input and the output back to the PCM which will vary progressively/linear from .4 vdc at idle to around 4.5 vdc at WOT (wide open throttle).

[magnoliablossom]

Thanks bnaylor. I just wanted to be sure that was the part I really needed before I bought. I really appreciate the help and the quick reply.