2003 Chevrolet Tahoe: sudden loss of power

7 of the 507 complaints about the 2003 Chevrolet Tahoe describe sudden loss of power.

owner complaints: 7
of this car's complaints: 1%
recalls: 0

Is there a fix? 121 service bulletins cover this area of the car. See below

Sudden loss of power by model year

2026
10
2025
5
2024
7
2023
21
2022
12
2021
49
2020
5
2019
12
2018
1
2017
8
2016
10
2015
22
2014
2
2013
5
2012
2
2011
5
2010
3
2009
7
2008
11
2007
18
2006
1
2005
2
2004
7
2003
7
2002
5
2001
2
2000
3
1999
5
1998
2
1997
6
1996
4
1995
2
1994
2

What owners say

Filed Jul 23, 2015 · Driver assistance, Electrical · 220,000 miles · IL

While driving on the interstate at 70 MPH the car switched to reduced engine power and reduced speed immediately to 25 MPH, leaving me in the position to navigate through rush hour traffic to get to the side of the road. After happening a couple of times over a 30 period, it is now a regular occurrence. Each attempt to take the car in to a mechanic to be repaired results in the same issue occurring afterwards. Mechanics seem not to be able to determine the cause resulting in a completely unsafe car. The throttle body has been replaced, wire harness, pedal sensor, and throttle body sensor. Nothing has solved the problem!

Filed Jan 18, 2012 · Electrical, Fuel system · VA

I can be going down the highway running 65-70 MPH and the reduced engine power light will come on and reduces my speed to 10 MPH! I pull over, disconnect the battery cable and replace it, then I could continue for another week or so. Finally, I left the diagonstic computer in my truck and was able to capture the code p1125. The mechanic said to replace the throttle body. That was done in october. It ran fine for a while, but it started doing it again. The throttle body was replaced again! Now, two months later, it's doing it again! No one can seem to fix the problem. Meanwhile, I am a female who travels the highways everyday going back and forth to work and I have been in several dangerous situations due to this problem that will not stop! As of now, I can not drive my truck and having to rely on carpooling again until it's fixed for the third time in the past 6 months. It also appears that several people are having the same problem with no results. Someone is going to get killed if this is not addressed soon!

Filed Jun 10, 2011 · Engine · 104,000 miles · OH

The reduced engine power light came on and reduced the car's power to only be able to go 20 MPH. I did reach 30 MPH with a down-slope. I was very scared and had my two children in the car. Thankfully, I was able to safely pull over to the side of the road. Upon researching this issue with my car make and model, it seems to be a common problem and a very serious issue. The engine's power just pulled back without warning! I am taking the car to be serviced tomorrow but cannot fathom to think what could have happened!

Filed Jun 24, 2008 · Engine, Lights · 38,416 miles · MA

When starting the vehicle, check engine light comes on and dash says reduced engine power. Vehicle will only drive about 15 miles per hour. Upon researching this through various internet websites, this same problem has and is happening to a huge amount of 2003 tahoe owner's and it's always a faulty wiring harness problem - yet gm refuses to acknowledge there is a problem. On a side note, headlights have always been very dim.

Filed Aug 25, 2004 · Engine · 18,971 miles · CA

While driving vehicle lost power. Vehicle would not accelerate over 10 MPH. Dealership was notified, but did not resolve the problem.

Filed Mar 6, 2004 · Engine · CA

"reduced engine power" message displayed 3 times within 4100 miles of brand new tahoe. On 4th visit, dealer replaced throttle body with a new one at 4366 miles.

Filed Oct 15, 2003 · Engine · CA

Vehicle experienced a total immediate loss of power while driving.*mr almost rear ended another vehicle at a high speed twice during the last break down on a busy highway. The consumer was very dissatisfied with the dealership help in assisting with vehicle. Please investigate