HomeTrouble CodesP0229

P0229 — Throttlepedal Position Sensorswitch C Circuit Intermittent

Generic OBD-II · all makesPowertrain (engine & transmission)

Code P0229 indicates that the engine computer has detected an intermittent or erratic electrical signal from the 'C' circuit of the throttle pedal position sensor. This means the voltage or resistance from the pedal sensor is dropping out or spiking momentarily, which disrupts the computer's ability to accurately read driver acceleration demands.

Symptoms

What causes it — most likely first

1. Defective throttle pedal position sensor

The internal electronics of the sensor itself can degrade, causing momentary signal dropouts or erratic voltage readings.

2. Wiring or connector issues

Corroded, loose, or chafed wiring and terminals in the pedal sensor circuit can cause the electrical signal to intermittently cut out.

3. Throttle pedal assembly mechanical binding

Physical obstructions, carbon buildup, or worn pivot points can cause the pedal mechanism to stick and send erratic data to the computer.

4. Power or ground supply fluctuations

A poor ground or unstable reference voltage to the sensor can cause the signal circuit to read intermittently.

5. Engine computer (PCM/ECM) failure

An internal fault within the computer causing it to incorrectly process or lose the sensor signal is extremely rare and should only be considered after all other possibilities are eliminated.

How it's diagnosed

  1. Scan the vehicle for additional codes and capture freeze frame data to see the exact conditions when the P0229 code set.
  2. Visually inspect the throttle pedal position sensor connector and wiring harness for signs of damage, corrosion, or loose pins.
  3. Monitor the throttle pedal position sensor 'C' signal on a scan tool while gently wiggling the wiring and tapping the sensor to reproduce the intermittent fault.
  4. Use a multimeter to check the reference voltage and ground circuits at the sensor connector to ensure they are stable and within specifications.
  5. If the wiring and power supplies test fine but the signal remains intermittent, replace the throttle pedal position sensor.
  6. Only consider engine computer diagnostics or replacement if the new sensor and verified wiring do not resolve the intermittent signal.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Can I still drive my car with a P0229 code?

It is not recommended. The vehicle may suddenly enter reduced power mode or lose accelerator response, which creates a dangerous situation in traffic.

Is the throttle pedal position sensor the same as the throttle body position sensor?

No, they are separate components. The throttle pedal position sensor is mounted on the accelerator pedal inside the cabin, while the throttle body position sensor is on the engine's intake.

Will replacing the PCM fix a P0229 code?

No, replacing the engine computer is almost never the correct fix for this code. The vast majority of the time, the issue is a failing pedal sensor, a wiring defect, or a poor connection, and the PCM is incorrectly blamed.

Can a bad ground cause this intermittent code?

Yes, a poor ground connection can cause the sensor's voltage signal to fluctuate erratically, triggering an intermittent circuit code like P0229.