P2109
Throttle/Pedal Position Sensor A Minimum Stop Performance
Throttle / air metering
Generic OBD-II
Medium
What it means
P2109 means the throttle position sensor's reading at the closed (minimum) throttle stop doesn't match what the ECM expects. On drive-by-wire engines this upsets idle and throttle control, so the car may idle poorly, hesitate, or drop into a reduced-power limp mode. It usually points to a throttle sensor, wiring, or carbon-buildup problem rather than a serious engine fault.
Medium
Can I keep driving? Usually still driveable, but the electronic throttle may drop into a reduced-power limp mode — avoid hard acceleration and get it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or a forced limp/failsafe mode
- Rough, high, or unstable idle
- Hesitation when accelerating
- Occasional hard starting
Common causes
Most likely first
- Faulty throttle position sensor / throttle bodyLikely
- Open or shorted wiring in the throttle position sensor circuitCommon
- Poor or corroded connector at the throttle bodyCommon
- Dirty or carbon-filled throttle bore throwing off the learned closed-throttle stopLess often
- Faulty engine control module (ECM) — rareLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then check the throttle position sensor connector with the key on: look for a steady 5-volt reference and a clean ground.
- Inspect the wiring and connector for damage, corrosion, or a loose pin.
- Clean carbon buildup from the throttle bore, which can shift the minimum-stop position.
- If readings are still out of range, replace the throttle body/sensor and perform the idle/throttle relearn.
FAQ
Quick answers
Is it safe to drive with P2109?+
Short-term yes, but the throttle can enter a reduced-power limp mode with little warning, so avoid highway or heavy-traffic driving until it's fixed.
Can I just clear P2109?+
It will come back until the sensor, wiring, or throttle-body carbon is addressed. After a real repair, an idle relearn is often needed for the code to stay away.
Related codes
Often seen with P2109
Read & clear P2109 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