STUPID DAMN reduced engine power my truck was fine till i decided to drive it home from work then it started saying "reduced engine power" on my dash and it wouldnt let me go above 1500 rpm. I have searched a few other threads but no body has really said anything about what they did to fix it? did swapping out the TB fix the problem or was it a bad ground? can someone help me please


thanks

 

REP can come on for numerous reasons. Scan for codes to point in the right direction. Any number of sensors or tune. Any answers you get would be guesses without the codes.

 

read the code a few min ago and it reads "tbs" something like that. So i guess will start there. Man it sucks seeing your truck down

 

TBS or TPS?

 

TPS sorry

 

Yea. Throttle position Sensor will definitely do it.

 

 

The Throttle Position Sensor failure or discriminating value can trigger a Reduced Engine Power DTC. But you need to look at the bigger or entire picture. Your truck (if it's a 2003 and up) has a Throtle Pos. Sensor which is directly proportional to the ETC (Electronic Throttle Control) which is operated by the TAC Module (Throttel Actuated Control) and the Electronic Throttle Body. All of these parts analyze the values that the Throttle Pos. Sensor is feeding into the TAC Module, then the TAC module relays the information through the PCM and into the Elec. Throttle Body which decides how far to open or close the throttle blade to allow more air to enter for the correct amount of air & fuel combustion.

This being said, any problem with the Elec. Throttle Body, the TAC Module or the TPS Sensor can cause a Reduced Engine Power problem. I personally have seen this 3 times in my shop because a customer has installed a Ported Throttle Body or a larger BBK throttle body on their vehicle and tried to use the OEM "stock" tune. In all 3 cases the Throttle Bodies were installed on basically a stock truck, a truck with an exhaust and a Granatelli Mass Air Sensor with no screen.

Twice the problem was corrected by re-installing the OEM Throttle Body. The 3rd was fixed by replacing the Granatelli MAF Sensor with the OEM unit and OEM Throttle Body. All 3 episodes could have probably been fixed with a good tune done by a reputable professional tuner. But the OEM tune from GM just does not support these upgrades, and the new data being collected by the systems sensors are showing far diffrent from what "stock" is suppoosed to be. So it will go to a failsafe program like reduced Engine Power to try to not damage anything.

I would say if you ask someone like Allen Nelson @ nelson performance or anyone that does an extensive amount of tuning, they have probably seen this also, and they tweak the tune to compensate for the increase.

Hope the longwinded response has been helpful.