P2104
Throttle Actuator Control System - Forced Idle
Throttle control
Generic OBD-II
High
What it means
P2104 means the engine control module has put the electronic throttle into a fail-safe "forced idle" state: it detected a throttle-control fault and, to stay safe, limits the engine to idle so the vehicle won't accelerate. It's a protective response — usually to another throttle or pedal-sensor fault — rather than the root problem. The car will start and idle but can only crawl until repaired.
High
Can I keep driving? Barely drivable — the engine is forced to idle and won't accelerate, so the vehicle can only crawl. Pull over safely and have it repaired or towed.
Common symptoms
What you'll notice
- Check-engine light on (often with a warning/wrench light)
- Engine limited to idle — little or no throttle response
- Severely reduced power / limp (fail-safe) mode
- Vehicle will not accelerate past a crawl
Common causes
Most likely first
- Underlying throttle actuator or throttle body fault triggering fail-safeLikely
- Throttle position sensor or accelerator pedal position sensor faultCommon
- Wiring, connector, or ground problems in the throttle control systemCommon
- Dirty or sticking throttle bodyLess often
- Faulty engine control module (ECM/PCM)Less often
How to diagnose & fix
Work through it in order
- Scan for companion throttle/pedal codes (P2100-P2103, P0121, P0221) — P2104 is usually a fail-safe reaction to another fault.
- Inspect the throttle body and accelerator pedal connectors and wiring for damage, corrosion, or poor grounds; repair as needed.
- Clean the throttle body if it's carboned or sticking, then reset and re-learn the throttle.
- Test the throttle position and pedal position sensors against spec; replace any out-of-range sensor.
- If sensors and wiring check out, have the ECM/PCM evaluated. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2104?+
No. The engine is locked to idle and won't accelerate, which is unsafe in traffic. Pull over, and repair or tow the vehicle.
Can I just clear P2104?+
Clearing it may briefly restore throttle, but it returns as soon as the underlying throttle fault reoccurs. Diagnose the root cause.
Related codes
Often seen with P2104
Read & clear P2104 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX