Page updated on 06-21-2018

reduced engine power

07-03-2009, 06:49 PM
I have a 2005 pontiac grand pix that has been giving me the reduced engine power signal. i took it in to have the codes read and it gives me codes p1125 and p2138. someone suggested i clean the throttle plate which helped for awhile, but its doing it again.any suggestions on how i should go about fixing this.

07-04-2009, 10:08 AM
Welcome to AF!!

The one code the P1125 indicates that the throttle position sensor is probably going bad. I would replace it after cleaning the throttle body. A good cleaning can't hurt. The throttle position sensor tells the computer to send fuel to the engine. If the tps is not working correctly it doesn't send a correct signal and the engine doesn't get the required fuel to make power. As for the other code, I can't find a reference that will give me an explanation so maybe someone else can help with that one.

07-04-2009, 03:53 PM
It would help to post what engine. The '04 and up technically DO NOT have a throttle position sensor (TPS) like the previous generation '97 - '03. It is "drive by wire" and a control module (TAC - Throttle Actuator Control) at the throttle body throttle plate.

DTC P2138 like the P1125 is an Accelerator Pedal Position Error (APP).

BTW - GM has various TSBs out on "drive by wire" issues so a trip to the dealership may be necessary.

07-17-2009, 06:23 PM
I have v6 05 pontiac grand prix. i did have someone order a new accelerator pedal to change out and the car felt alot better when driving. of course it did end up shutting off again and gave the same codes.

Add your comment to this topic!