P2139
Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation
Throttle / air metering
Generic OBD-II
Medium
What it means
P2139 means two of the redundant throttle/pedal position signals ("D" and "F") don't agree with each other. These sensors are doubled up for safety, so when their voltages don't correlate the ECM can't trust the pedal input and usually defaults to reduced power. The cause is typically a failing sensor or wiring fault between the circuits, not an engine mechanical problem.
Medium
Can I keep driving? Commonly triggers a reduced-power limp mode as a safety default — driveable gently, but acceleration is limited, so fix it before highway use.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power / forced limp (failsafe) mode
- Poor or inconsistent throttle response
- Hesitation or surging on acceleration
Common causes
Most likely first
- Faulty pedal/throttle position sensor (D or F element disagreeing)Likely
- Open, shorted, or chafed wiring between the two sensor circuitsCommon
- Poor or corroded connector at the pedal or throttle sensorCommon
- Faulty engine control module (ECM) — rareLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then compare the D and F signals in live data to see which one is out of range.
- Inspect the connector and wiring for corrosion, damage, or shared-circuit shorts.
- Verify each circuit has its 5-volt reference and clean ground, key on.
- If the two signals won't track together after wiring is confirmed good, replace the pedal/throttle position sensor.
FAQ
Quick answers
Is it safe to drive with P2139?+
Only cautiously. The two disagreeing signals usually force reduced power for safety, so acceleration is limited — avoid highway merging until it's repaired.
Can I just clear P2139?+
It returns as soon as the sensors disagree again. The two signals must track together correctly, which means fixing the sensor or its wiring.
Related codes
Often seen with P2139
Read & clear P2139 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