P2129
Throttle/Pedal Position Sensor/Switch E Circuit Intermittent
Throttle / air metering
Generic OBD-II
Medium
What it means
P2129 means the ECM saw an intermittent or erratic signal from throttle/pedal position sensor "E." Because the reading comes and goes, the fault points strongly at a wiring or connector problem rather than a constant sensor failure. On drive-by-wire systems these dropouts can briefly cut power or trigger limp mode, so it's worth chasing down even if the car mostly drives normally.
Medium
Can I keep driving? Often driveable, but an intermittent pedal/throttle signal can cause sudden reduced-power or limp mode without warning — get it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Intermittent reduced power or limp (failsafe) mode
- Surging or inconsistent throttle response
- Rough or unstable idle at times
Common causes
Most likely first
- Loose, corroded, or poor connector at the sensor (most common with an intermittent fault)Likely
- Chafed, open, or intermittently shorted wiring in the 'E' sensor circuitCommon
- Faulty throttle/pedal position sensor ECommon
- Faulty engine control module (ECM) — rareLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then wiggle-test the sensor connector and harness while watching live data for signal dropouts.
- Inspect the connector and pins for corrosion, spread terminals, or a loose fit; reseat or repair as needed.
- Check the circuit for a steady 5-volt reference and clean ground, and look for chafed wiring.
- If the signal still drops out, replace the position sensor and clear the code.
FAQ
Quick answers
Is it safe to drive with P2129?+
Usually short-term, but because the fault is intermittent the throttle can drop into reduced power at random. Have it diagnosed before relying on the car in traffic.
Can I just clear P2129?+
You can, but an intermittent wiring or connector fault will set it again. The real fix is finding and repairing the loose or chafed connection.
Related codes
Often seen with P2129
Read & clear P2129 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