What it means
The throttle plate cannot be commanded open. The engine stays at idle or stalls under load. Often caused by a seized motor, broken gear, or heavy carbon coking inside the throttle bore.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The throttle actuator control system opens the throttle plate to admit air as the driver requests acceleration. P2112 sets when the control module commands the plate to open but detects that it remains at or near the closed position, which can leave the engine unable to produce enough power.
Common causes
Most likely first.
- Throttle plate seized closed
- Throttle motor seized or gear broken
- Carbon or debris buildup preventing free movement
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Use a scan tool to save freeze-frame data and compare commanded with actual throttle position while checking for related actuator, position, or power-supply codes.
- Inspect the throttle bore and plate for heavy deposits or debris that may prevent opening, following the vehicle's service guidance.
- Check the throttle actuator connector and harness for loose pins, corrosion, damaged insulation, or a broken wire.
- Use an available scan-tool actuator test to see whether the plate responds to an opening command and whether position feedback changes.
- If the plate is unobstructed and wiring is sound, test the actuator motor, gears, and position feedback against the manufacturer's specification.
Common fixes
- Clean deposits or remove debris preventing the throttle plate from opening, using the approved service procedure.
- Repair a loose or damaged throttle actuator connector or wiring fault.
- Replace a failed throttle motor or damaged gear mechanism after testing confirms it.
- Replace a faulty position sensor or throttle body assembly if its feedback or movement remains out of specification.
Can I keep driving?
Avoid driving in traffic or on roads where acceleration is needed; the engine may stay at idle or stall under load. Move to a safe place and arrange repair if the vehicle cannot accelerate predictably.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.