Throttle Actuator Control Module Throttle Actuator Position Performance (GM)
What does P1516 mean?
The P1516 code means the vehicle's onboard diagnostic system has detected: Throttle Actuator Control Module Throttle Actuator Position Performance (GM). This is a critical severity code.
Common Symptoms
- Reduced Engine Power message on dash
- Check Engine Light illuminated
- Engine limited to very low power
- Vehicle barely accelerates
- Traction control and stabilitrak warning lights on
Probable Causes (Ranked by Likelihood)
- Failed electronic throttle body Very High
- Throttle actuator control module failure High
- Corroded throttle body connector or wiring High
- Failed accelerator pedal position sensor Moderate
- ECM internal fault Low
Step-by-Step Diagnostic Procedure
-
Clean the throttle body first as carbon buildup is the most common trigger.
-
Check the throttle body connector for corrosion. GM throttle bodies are known for connector corrosion.
-
Monitor TPS1, TPS2, APP1, APP2, and APP3 signals on a scan tool for erratic readings.
-
Perform a throttle body relearn after cleaning.
-
If cleaning does not resolve the issue, replace the throttle body assembly and perform a relearn.
Frequently Asked Questions
Why is this rated critical?
P1516 severely limits engine power, making the vehicle barely drivable. While the engine will not be damaged, the vehicle may not be able to maintain highway speed or safely merge into traffic.
Is this a common GM problem?
Yes. The electronic throttle body on GM trucks and SUVs from 2003-2013 is one of the most commonly replaced components. The throttle body motor and sensors wear out over time.
Can I drive with Reduced Engine Power?
Only for short distances to reach a safe location or repair shop. The engine is limited to roughly 15-20% power, which is insufficient for normal driving conditions.