P2621
Throttle Position Output Circuit Low
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.
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.
Related codes
Often seen with P2621
Read & clear P2621 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