Throttle Actuator Control System - Forced Idle
The engine control module has detected a problem with the throttle actuator control system, forcing the engine to idle.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is telling the engine to idle because it found a problem with the throttle control. This usually means that the throttle won't respond correctly to your pedal input.
What the computer is actually seeing
The Engine Control Module (ECM) monitors the throttle position sensor (TPS), accelerator pedal position sensor, and throttle actuator. If it detects a discrepancy indicating that the throttle is stuck or not responding properly, it triggers this code.
What a healthy reading looks like
Throttle position sensor should read between 0.5V (closed) to 4.5V (fully open). Accelerator pedal position sensor should show a corresponding voltage increase when the pedal is pressed.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the throttle body for any physical obstructions or carbon buildup. Clean if necessary. Decision point: If clean, proceed to step 2; if obstructed, rectify and retest.
- 22. Inspect wiring and connectors to the TPS and accelerator pedal for damage, corrosion, or disconnection. Decision point: If all connections are secure, proceed to step 3; if damaged, repair or replace as necessary.
- 33. Using a scan tool, check the voltage readings from the TPS and accelerator pedal position sensor. They should match expected values. Decision point: If readings are within spec, test the throttle actuator; if not, replace the faulty sensor.
Common causes
- Faulty throttle position sensor (TPS)
- Faulty accelerator pedal position sensor
- Wiring issues between sensors and the ECM
- Vacuum leaks affecting throttle operation
- Failed throttle actuator motor
Typical repair cost
$150-$500
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive. The vehicle may go into limp mode, limiting your throttle response.
Will this code come back after I clear it?
It can come back if there's still an underlying issue with the throttle system.
Why does this code sometimes pair with P0120?
Both codes are related to throttle position issues; one refers to the sensor itself, while the other deals with the actuator's response.
Working a real vehicle right now?
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