2004 GMC Envoy Logo
Posted on Jul 08, 2010
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What does reduced engine power light mean and have no acceleration. Turned truck off and reduced engine power went out and everything is ok again; however afraid to drive the truck anywhere now. 2004 GMC Envoy

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Steven Gepner

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  • Expert 69 Answers
  • Posted on Jul 08, 2010
Steven Gepner
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Joined: Jul 07, 2010
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This model has what they call fly by wire.. no accelerator cable. If the computer detects a problem in the thottle system it will not allow the engine to accelerate and will show reduced power and possibly set a check engine light. The dealer usually wants to replace the throttle assembly which is very expensive and usually un nessesary.
I have had a lot of succes with just cleaning the throttle plates real good.

  • jeanne cushing
    jeanne cushing Dec 06, 2013

    thank you i will ask my mechanic to do that . is it a long job?

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0helpful
1answer

XL. Why is 'reduce eng.' light on?

Reduced engine power is a problem with the electronic throttle control . You need to have a scan tool hooked up to read codes stored .

REDUCED ENGINE POWER: Refer to Powertrain Control Module Description in Engine Controls - 4.8L, 5.3L, and 6.0L

Reduced Engine Power Mode
When the PCM detects a problem with the throttle actuator control (TAC) system the PCM enters one of the following Reduced Engine Power Modes:
• Acceleration Limiting--The control module will continue to use the accelerator pedal for throttle control, however the vehicle acceleration is limited.
• Limited Throttle Mode--The control module will continue to use the accelerator pedal for throttle control, however the maximum throttle opening is limited.
• Throttle Default Mode--The control module will turn off the throttle actuator.
• Forced Idle Mode--The control module will perform the following actions:
- Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.
- Ignore accelerator pedal input.
• Engine Shutdown Mode--The control module will disable fuel and de-energize the throttle actuator.
0helpful
1answer

My engine speed reduced light came on along with traction turned off on my 2009 Pontiac g6. when i accelerate it jerks.

Reduced engine power on GM vehicles has to do with the electronic throttle control .( Electronics ) Your best bet is to take your vehicle to a qualified repair shop or a GM dealer ! GM Reduced Engine Power Mystery Solved 04 Silverado REDUCED ENGINE POWER Case Study Part 1

0helpful
1answer

Reduced engine power

Have the vehicle checked for DTC'S - diagnostic trouble codes ! Do you know what electronic throttle control is ? The gas pedal assembly has electrical connector an sensors inside ,hooked to the PCM / ECM - engine computer . The engine computer uses these position sensors inputs to control the DC motor on the throttle body to open the throttle plate to control the speed . Plus there are position sensors inside the throttle body to input PCM/ECM to see if it's calculations are corect . Your best bet maybe to take it to a qualified repair shop .
Drive by Wire Function and diagnostics by Wells

Reduced Engine Power Mode
When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The control module will perform the following actions:
- Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.
- Ignore accelerator pedal input.
• Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.
0helpful
1answer

Reduced Engine Power and then died

If it does it again go to a auto parts stor and ask them to put the scan tool on it and get the codes pulled. Write them down and post them on here. You may be able to get codes now. It probably stored the codes in the cars computer.
0helpful
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0helpful
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Reduced Engine Power light

With GM vehicles a Reduced Engine Power message has to do with the electronic throttle control .


GM Chevy Truck REDUCED ENGINE POWER Case Study Part 1
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My 04 3.5 i5 4x4 recently stalled out on me. i was at a stop sign and when i accelerated it seemed as though it wanted to turn off. Almost got hit too!! So i pulled over and it was shaking and the rpms...

This sounds familiar! My truck stalls out and it reads "reduced power" and it fires back up in 5 mins or so. and the engine light stays on. The local GM dealer and a independent mechanic can't figure it out?
0helpful
1answer

My stabalink trac light came on and the engine light came on saying it was reducing power, it felt sluggish and went about 30 mph.

{: ) The stabiltrak light is just an after effect of the check engine light. When the system detects inconsistencies with the accelerator pedal position and throttle position sensors, it will enter into "Limp Mode", engine power will be reduced and you cannot accelerate normallly as you expected. So that you can LIMP your way back home, or to a nearest service shop. A P2138 code may be set, or its conjunctions. Before you decide to have it serviced, if you have the time, try to disconnect the connector at the accelerator pedal. Check for any backed out terminals. Then reconnect again firmly. When you hear it clicks in, it's firmly seated. Testdrive. If not okay, you do the same thing to the throttle position connector. It's on the side of the throttle body. I hope you get lucky.
0helpful
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I have a 2003 Saturn L300 6 cylinder. Last week the reduced power light came on and stays on every time the car is driven. The car performs the same but the heater is not working normally. Takes longer to...

This has nothing to do with the heat on the vehicle .
Reduced Power
The reduced power telltale is turned ON by the cluster when it receives a command from the body control module (BCM). The engine control module (ECM) (L81) engine sends a message to the BCM over the CAN serial data link.
The reduced power telltale is illuminated when the ECM is limiting engine torque in a low traction situation. This telltale is used only for the V6 (L81) engine application.
The reduced power telltale is turned ON by the cluster for 2-3 seconds, when the ignition is turned to RUN, for a visual system check.

Taking the vehicle to a qualified repair shop an having it diagnosed would be your best . Unless you have a factory tech 2 scan tool to read BCM DTC'S - diagnostic trouble code's an have factory diagnostic repair info.
Reduced Engine Power Mode
When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The ECM will perform the following actions:
• Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
• Ignore the accelerator pedal input.
• Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
3helpful
2answers

Code drive 5 . My 2004 trailblazer posted a code "drive 5". It showed the "reduced engine poweer" light, and would not respond to the accelerator pedal. I had been driving in slow traffic. I pulled over,...

Thottle body sensor, accelerator pedal sensor, restricted air flow...will all trigger this fault light. Go to your local Autozone, they will run an OBD scan for free, and explain the fault codes to you so the correct repairs can be made.
Good luck...i hope this helps, please rate me a fixya.
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