P2109

Throttle/Pedal Position Sensor A Minimum Stop Performance

Q: 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.

Q: 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.

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.

Real-world scan data

Seen in

146

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Appears alongside · share of P2109 scans

P1604in 34.2% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear P2109 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX