2003 GMC Sierra 2500: sudden loss of power

7 of the 160 complaints about the 2003 GMC Sierra 2500 describe sudden loss of power.

owner complaints: 7
of this car's complaints: 4%
recalls: 0

Is there a fix? 44 service bulletins cover this area of the car. See below

Sudden loss of power by model year

2025
3
2024
4
2023
4
2022
2
2021
2
2020
3
2019
1
2018
2
2017
3
2016
3
2015
6
2014
2
2013
2
2012
2
2007
2
2006
1
2004
4
2003
7
2002
3
2001
5

What owners say

Filed Feb 5, 2018 · Acceleration · 217,000 miles · MD

Complaint involves reduced power mode while driving. This has become a safety concern because of the rapid drop in speed while driving. It is unsafe trying to exit traffic lanes with no response from throttle pedal and appears to be a common problem with drive by wire vehicles produced by general motors. Vehicle has been to dealership twice with no resolution of the problem. This failure has occurred at various speeds, times of day, temperatures etc. It will enter reduced power once to twice a day. Thank you for your time.

Filed Apr 26, 2016 · Engine, Transmission · 180,000 miles · LA

Tl* the contact owns a 2003 gmc sierra 2500. While driving at any speed, the vehicle stalled, lost power, and the service engine light illuminated. The vehicle was taken to an independent mechanic who was unable to diagnose the failure. The failure recurred. The manufacturer was made aware of the failure and advised the contact to take the vehicle to a local dealer for diagnostic testing. The vehicle was not diagnosed or repaired. The failure mileage was 180,000.

Filed Apr 10, 2015 · Electrical, Fuel system · 142,000 miles · CT

(electrical) as an ongoing issue, the dashboard gauges/indicators (I.e. Tach, speedometer, etc..) will sometimes not register until several minutes after the vehicle has been running (this could be for up to miles) it has not affected vehicle performance to date. (fuel/propulsion system) I have begun having issues where it goes into "reduced engine power". Further diagnostic attempts have LED me to believe that it is due to a faulty throttle position sensor (part of the throttle body), tac module, or app assembly (accelerator pedal). Most likely cause may be due to the throttle position sensor, as this issue has happened when the vehicle is on "cruise control". However, due to the inferior design of the throttle body unit itself, the manufacture has made it difficult or if designed to be impossible to replace just the tps, by riveting the tps to the throttle body, and may have to replace the whole throttle body. I am having the vehicle serviced for a complete diagnostic and repair, and will elaborate further upon successful repair if desired.

Filed May 7, 2014 · Engine, Transmission · ME

Tl* the contact owns a 2003 gmc sierra 2500. The contact stated that there was a loss of power while traveling at any speed. The warning light illuminated for loss of power intermittently. The contact had to depress the acceleration pedal to the floorboard to accelerate on more than one occasion but to no avail. The vehicle continued to stall without warning. The vehicle was taken to an authorized dealer more than five times, who was not able to replicate or determine the cause of the failure. The vehicle had also been taken to the dealer for diagnosis but to no avail. The manufacturer was notified of the failure. The approximate failure mileage was not available.

Filed Mar 12, 2014 · Acceleration · AK

Issue with throttle body reduced engine power when driving throws out check engine light. Thousand of people have this same issue most have just stopped driving their vehicle like I have because it's unsafe to drive. I hoping not just for me but everyone out there with this same issue to get a recall before it kills someone. I haven't been able to drive my truck in three years.

Filed Sep 18, 2013 · Acceleration, Engine · 124,000 miles · NY

I keep getting reduced engine power p1516 code . Reading the post's on the internet this is a real common problem.also the speedometer will display 120 MPH sitting at a traffic light.

Filed Dec 13, 2011 · Acceleration, Engine · MA · crash

While driving on the highway, my 2003 gmc sierra 2500 displayed a "reduced engine power" warning on my dashboard. My vehicle lost all speed control, decelerating from 65 MPH to 20 MPH in a matter of seconds. I immediately pulled over to the side of the highway and shut my truck off. Once I restarted the vehicle, the message was gone and my truck was fine. It was a very scary incident not being able keep the right speed for the conditions on the highway.