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P0229 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch C Circuit Intermittent

Check Engine Light

P0229 code definition

Throttle/Pedal Position Sensor/Switch C Circuit Intermittent

What the P0229 code means

P0229 is an OBD-II generic code indicating the throttle/pedal position sensor/switch C circuit has an intermittent input problem causing the sensor input to the engine control module (ECM) to be intermittent and within the the expected voltage input when compared to the throttle position sensor A.

What causes the P0229 code?

  • The engine control module (ECM) detects erratic input voltage from the sensor circuit to the ECM, but still within the specified range for the sensor when it is working.

  • Corrosion in the connections to the sensor can cause the erratic voltages from the sensor.

  • Loose connections to the sensor can cause the voltage to be erratic.

What are the symptoms of the P0229 code?

  • The Check Engine and Electronic Throttle Control (ETC) Light will be illuminated

  • The ECM will go into failure limp home mode and drive complaints may vary depending on manufacturer programming

  • The throttle is shut completely during stops to prevent excessive RPM’s when stopping the vehicle

  • The throttle may be set to a fixed position during acceleration to limit throttle opening

  • Uneven idle or jerking during braking due to the closed throttle position

  • Very poor throttle response during acceleration or no response at all limiting acceleration

  • The vehicle speed will be limited to 32 mph or less

  • The symptoms may go away if the vehicle is restarted, but the Check Engine Light will remain until repairs are done or codes are erased

How does a mechanic diagnose the P0229 code?

  • Scans codes and documents the freeze frame data in order to verify the problem

  • Clears the engine and ETC codes to verify concern comes back

  • Does a visual check of the wiring and connections to the throttle body sensors for loose or corroded connections

  • Checks scan data to see if sensor signal voltage is erratic while doing a wiggle test of the connector and wiring to find cause of the intermittent connection problem

  • Disconnects and checks the sensor resistance to see if the sensor is having an internal intermittent circuit failure by exercising the throttle plates and lightly tapping the sensor to simulate road shock

Common mistakes when diagnosing the P0229 code?

Follow these simple guidelines to prevent misdiagnosis:

  • Simulate road shock to sensor while monitoring data to isolate failure in the sensor or in the connection and wiring

  • Look for any problems with burnt or cut wiring to the sensor or corrosion in the connections that can cause erratic voltage output

How serious is the P0229 code?

  • Any problems with the throttle sensor causes the limp mode to be activated.

  • The engine will go into limp home mode and systems will be limited depending on manufacturer.

  • The vehicle speed will be limited to less than 35 mph.

  • The engine will lack acceleration or have limited acceleration.

  • The engine idle will be low and erratic when coming to a stop.

  • The vehicle fails emission testing.

What repairs can fix the P0229 code?

  • Repairing or replacing wiring or connections to the sensor

  • Replacing a defective throttle body control assembly for internal faults

  • Replacing or reprogramming the ECM if directed by the pinpoint tests after all other tests pass and no other faults with the sensor or wiring is found

Additional comments for consideration regarding the P0229 code

Code P0229 is caused by erratic or intermittent signals from the sensor to the ECM. These signals are still within the specified range of the sensor when the signal is being received by the ECM.

Need help with a P0229 code?

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The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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