Reduced Engine Power
Chevrolet Vehicle
Severity: CriticalWhat Does This Error Mean?
Reduced Engine Power means the engine computer has limited power output to protect the engine or transmission. The car may barely accelerate above 20-30 mph. Common causes: throttle body, accelerator pedal sensor, or wiring harness.
Affected Models
- Chevrolet Silverado
- Chevrolet Equinox
- Chevrolet Malibu
- Chevrolet Traverse
- Chevrolet Tahoe
- Chevrolet Impala
Common Causes
- Electronic throttle body failure
- Accelerator pedal position sensor fault
- TAC (Throttle Actuator Control) module wiring issue
- Engine coolant temperature sensor reading too high
- Mass airflow sensor failure
How to Fix It
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Pull over safely, turn off the engine, wait 1 minute, restart.
Sometimes a restart clears the reduced power mode. If power returns to normal, the issue was a temporary sensor glitch.
-
Check the throttle body connector.
A loose or corroded connector on the electronic throttle body is the #1 cause on GM vehicles. Unplug, inspect, clean with electrical cleaner, and reconnect.
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Have the fault codes read.
The specific code identifies whether it is the throttle body, pedal sensor, or wiring. P2135 (throttle position correlation) is very common.
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Check the wiring harness for chafing.
GM wiring harnesses are known to chafe against engine components. Look for damaged insulation on the throttle body and pedal position sensor wires.
Frequently Asked Questions
How much does a throttle body replacement cost?
Aftermarket: $100-$200. OEM GM: $250-$400. Labor: $100-$200. Total: $200-$600.
Can I drive in reduced power mode?
Yes, but very slowly. The car limits speed to about 20-30 mph. Drive carefully to a safe location or mechanic.