Rick's Free Auto Repair Advice

Reduced engine power Cadillac

Why is my reduced engine power warning on Cadillac

This post is for reduced engine power on a 2003 Cadillac Escalade, but it can apply to any vehicle with an electronic throttle body. These drive-by-wire systems have multiple safety features built in. If any of the multiple sensors gives an incorrect reading the system automatically defaults to a reduced engine power state as a safety measure.

As always, start by checking the trouble codes. Here’s an example of the codes you might see:

P2135 TP sensor signals 1 & 2 disagree or outside predetermined range

P1125 Accelerator pedal position sensors out of range or disagree

P0121 Throttle Position Sensor/Switch A Circuit Range/Performance Problem

At first glance you might automatically assume that you’re dealing with a bad electronic throttle body since both the throttle position sensor and accelerator pedal position sensors are out of whack. But that’s the clue that you’re probably dealing with something else, because the probability of both the TPS and APP going bad at the same time are pretty slim. However, both sensors do have something in common—they both need a ground. And any time you have a common ground in multiple circuits, you should check that first.


In this case, a reduced engine power was caused by a corroded ground for the electronic throttle body.

©, 2014 Rick Muscoplat

Posted on by Rick Muscoplat

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