P2621

Throttle Position Output Circuit Low

Q: Is it safe to drive with P2621?

You can usually drive gently, but if the engine drops into reduced-power mode, acceleration will be limited. Get it diagnosed soon — throttle faults affect control of the engine.

Q: Can I just clear P2621?

It returns until the sensor or wiring fault is fixed, and the engine may keep entering limp mode.

Fuel & air metering Generic OBD-II Medium

What it means

P2621 means the throttle position output signal is reading lower than expected. Because the computer relies on this signal to know how far the throttle is open and manage power, a low or lost signal can trigger a reduced-power limp mode for safety. It's an electrical or sensor fault, not a mechanical engine failure.

Medium

Can I keep driving? Often yes but with reduced power — a throttle-signal fault can drop the engine into a reduced-power 'limp' mode. Drive gently and get it checked soon.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

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 engine power or a 'limp' mode
Hesitation or poor throttle response
Possible rough or unstable idle

Common causes

Most likely first

Faulty throttle position sensorLikely
Open, shorted, or corroded wiring or connector in the throttle position circuitCommon
Loss of the 5-volt reference or ground to the sensorCommon
Dirty or carboned throttle body affecting the signalLess often
Faulty ECM/PCM (least likely)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame and check for related throttle codes (P2620, P2622, P2135).
Inspect the throttle/pedal position connector and wiring for damage or corrosion.
With the key on, verify a steady 5-volt reference and a good ground at the sensor.
Clean the throttle body if it's carboned, then retest the signal.
If wiring and reference are good, replace the throttle position sensor, then reassess the ECM.

FAQ

Quick answers

Is it safe to drive with P2621?+

You can usually drive gently, but if the engine drops into reduced-power mode, acceleration will be limited. Get it diagnosed soon — throttle faults affect control of the engine.

Can I just clear P2621?+

It returns until the sensor or wiring fault is fixed, and the engine may keep entering limp mode.

Read & clear P2621 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