P0229 is a Generic OBD-II Powertrain code indicating an intermittent problem with the Throttle/Pedal Position Sensor/Switch C circuit. The PCM/ECM has detected that the C position signal is intermittently lost, becomes unstable, or does not behave consistently.
The exact component represented by sensor C varies by vehicle. It may be integrated into the electronic throttle body or accelerator-pedal position assembly. Always use vehicle-specific service information to identify the correct sensor, connector, wiring and pinout.
What Does P0229 Mean?
P0229 means the PCM/ECM has detected an intermittent malfunction in the Throttle/Pedal Position Sensor/Switch C circuit.
Unlike P0227 or P0228, which describe a consistently low or high input condition, P0229 indicates that the signal can appear normal and then become abnormal, disappear, or change unexpectedly.
Is P0229 Generic or Manufacturer Specific?
P0229 is a Generic OBD-II Powertrain code. However, the exact sensor, wiring configuration, connector, pinout and diagnostic procedure are manufacturer-specific.
What Is Sensor C?
Sensor C is a designated throttle or accelerator-pedal position signal within the vehicle's electronic throttle-control system.
Depending on the vehicle, it may be integrated into:
- Electronic throttle body.
- Accelerator pedal assembly.
- Manufacturer-specific throttle/pedal position circuitry.
Many electronic throttle systems use multiple position signals so the PCM can compare them for safety and plausibility.
Where Is the P0229 Sensor Located?
If the C signal belongs to the throttle body, the position sensor is normally integrated into the electronic throttle body mounted on the engine intake system.
If the C signal belongs to the accelerator-pedal system, the relevant sensor is normally integrated into the accelerator pedal assembly inside the passenger compartment.
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APP Position Signals
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PCM/ECM
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Electronic Throttle Control
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Throttle Position Sensors
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Engine Torque Control
Driver Side or Passenger Side?
P0229 does not identify a vehicle side. The C designation identifies a particular sensor or signal circuit rather than the driver's or passenger's side.
Common Symptoms of P0229
- Check Engine Light.
- Intermittent loss of throttle response.
- Reduced engine power.
- Limp-home mode.
- Hesitation during acceleration.
- Intermittent surging.
- Delayed accelerator response.
- Engine may intermittently enter fail-safe mode.
- Possible stalling in severe cases.
Common Causes of P0229
- Intermittent throttle/pedal position sensor C fault.
- Loose electrical connector.
- Loose or damaged terminal.
- Corroded connector pins.
- Intermittent open circuit.
- Damaged wiring.
- Chafed wiring harness.
- Wire broken internally.
- Poor sensor ground.
- Intermittent reference-voltage problem.
- Signal-wire interference.
- Water intrusion.
- Faulty electronic throttle body.
- Faulty accelerator-pedal assembly.
- PCM/ECM fault, although this is less common.
Why Does P0229 Set?
The PCM continuously monitors the throttle and pedal position signals. If the C signal becomes intermittent or temporarily falls outside the expected operating behavior, the PCM may store P0229.
Intermittent faults can be difficult to diagnose because the signal may return to normal before the vehicle reaches the repair shop.
Typical Sensor C Signal
A properly functioning position signal should change smoothly and consistently according to throttle or accelerator-pedal movement.
For an intermittent fault, the signal may suddenly drop out, jump, become noisy, or temporarily disagree with another position signal.
There is no universal voltage specification for P0229. Always use the manufacturer's specifications for the exact vehicle.
How to Diagnose P0229
1. Scan for All Codes
Use a professional scan tool and record P0229 along with all stored, pending and related DTCs.
Related throttle and accelerator-pedal codes can provide important clues about the location of the fault.
2. Check Freeze Frame Data
Review engine RPM, vehicle speed, throttle position, accelerator position, engine load and other available data recorded when the fault occurred.
3. Monitor Live Data
Monitor the available throttle and accelerator-pedal position parameters while slowly operating the accelerator.
Look for:
- Sudden signal dropouts.
- Unexpected jumps.
- Intermittent fixed readings.
- Signal values that temporarily disappear.
- Incorrect correlation between redundant signals.
4. Perform a Wiggle Test
With the appropriate diagnostic equipment connected, carefully move the wiring harness and connectors while monitoring the sensor data.
If the signal changes when the harness or connector is moved, an intermittent wiring or terminal problem may be present.
5. Inspect the Connector
Check the connector for:
- Loose terminals.
- Corrosion.
- Water intrusion.
- Damaged pins.
- Broken locks.
- Poor terminal tension.
6. Inspect the Wiring
Look for chafing, damaged insulation, stretched wires, crushed sections, heat damage and previous repairs.
An intermittent internal wire break can be difficult to see because the outside insulation may appear normal.
7. Check Reference Voltage
Following the manufacturer's procedure, verify the required sensor reference voltage.
An unstable reference supply can affect multiple sensors and should be investigated before replacing the position sensor.
8. Check Sensor Ground
Verify the sensor ground according to the manufacturer's testing procedure. A poor ground can cause unstable or intermittent sensor signals.
9. Test the Signal Circuit
Use the vehicle-specific wiring diagram to identify the C signal circuit and perform the required continuity, resistance and circuit tests.
Do not assume that connector pin numbers or wire colors are the same between manufacturers.
10. Compare Redundant Signals
If multiple throttle or pedal position signals are available, compare their relationship while operating the accelerator.
An intermittent disagreement can help identify which circuit is malfunctioning.
11. Use an Oscilloscope
An oscilloscope is particularly useful for intermittent P0229 faults because it can capture brief signal dropouts or disturbances that a scan tool may miss.
12. Clear and Retest
After repairing the confirmed fault, clear P0229 and perform a functional and road-test verification while monitoring the relevant position signals.
Oscilloscope Diagnosis
A healthy position signal should normally change smoothly and consistently.
────╱╱╱╱╱╱────
Intermittent Dropout:
────╱╱──╲╱╱────
Signal Noise:
────╱╱╱╱╱╱────
╱╲╱╲╱╲
An intermittent dropout, sudden spike or unstable section of the waveform can help locate the problem.
The exact voltage range and waveform characteristics depend on the vehicle's sensor design.
P0229 vs P0225, P0226, P0227 and P0228
- P0225: Throttle/Pedal Position Sensor/Switch C Circuit.
- P0226: Sensor/Switch C Circuit Range/Performance.
- P0227: Sensor/Switch C Circuit Low Input.
- P0228: Sensor/Switch C Circuit High Input.
- P0229: Sensor/Switch C Circuit Intermittent.
The defining feature of P0229 is that the C circuit problem is intermittent rather than consistently low or high.
Can a Loose Connector Cause P0229?
Yes. A loose terminal or poor electrical connection can cause the position signal to intermittently disappear or become unstable.
Can a Broken Wire Cause P0229?
Yes. A wire that is partially broken internally can make and lose electrical contact as the engine or wiring harness moves.
Can the Throttle Body Cause P0229?
Yes. If the C position sensor is integrated into the throttle body, an internal sensor or circuit fault can cause an intermittent signal.
Can the Accelerator Pedal Cause P0229?
Yes, depending on the vehicle. If sensor C is part of the accelerator-pedal position system, an intermittent pedal sensor or internal connection can cause P0229.
Can Corrosion Cause P0229?
Yes. Corrosion increases electrical resistance and can create an intermittent connection, especially when vibration or temperature changes affect the connector.
Can a Weak Battery Cause P0229?
Low or unstable system voltage can contribute to electronic-control faults on some vehicles, but a persistent P0229 should be diagnosed at the sensor and circuit level.
Can a Dirty Throttle Body Cause P0229?
A dirty throttle body can cause mechanical throttle problems, but contamination does not automatically explain an intermittent electrical position-sensor signal. The electrical circuit should be tested first.
Is P0229 Serious?
P0229 can be serious. An intermittent throttle or pedal position signal can cause unpredictable throttle response or reduced engine power.
Some vehicles may enter fail-safe or limp-home mode when the PCM detects an unreliable throttle-control signal.
Can You Drive With P0229?
Driving with an intermittent throttle-control fault can be risky because the vehicle may suddenly reduce engine power or lose normal accelerator response.
If throttle response becomes unpredictable or the vehicle enters reduced-power mode, diagnose the fault before continuing to drive.
Possible Repairs
- Repair damaged wiring.
- Repair an intermittent open circuit.
- Repair loose connector terminals.
- Repair corroded terminals.
- Repair damaged connector pins.
- Correct reference-voltage problems.
- Repair sensor-ground problems.
- Replace a defective throttle body when confirmed.
- Replace a defective accelerator-pedal assembly when confirmed.
- Repair or replace the PCM/ECM only when diagnosis confirms a module fault.
Common Repair Mistakes
- Replacing the throttle body without testing the intermittent circuit.
- Replacing the accelerator pedal without inspecting the harness.
- Ignoring loose connector terminals.
- Failing to perform a wiggle test.
- Ignoring internal wire breaks.
- Using generic voltage specifications.
- Replacing the PCM too early.
- Clearing the code without reproducing and verifying the fault.
Recommended Diagnostic Tools
- Professional OBD-II scan tool.
- Bi-directional diagnostic scanner.
- Digital multimeter for approved circuit tests.
- Automotive oscilloscope.
- Back-probing test leads.
- OEM wiring diagrams.
- Manufacturer-specific service information.
Related DTC Codes
- P0120 – Throttle/Pedal Position Sensor/Switch A Circuit.
- P0121 – Sensor A Range/Performance.
- P0122 – Sensor A Low Input.
- P0123 – Sensor A High Input.
- P0220 – Throttle/Pedal Position Sensor/Switch B Circuit.
- P0221 – Sensor B Range/Performance.
- P0222 – Sensor B Low Input.
- P0223 – Sensor B High Input.
- P0225 – Throttle/Pedal Position Sensor/Switch C Circuit.
- P0226 – Sensor C Range/Performance.
- P0227 – Sensor C Low Input.
- P0228 – Sensor C High Input.
- P2135 – Throttle/Pedal Position Sensor A/B Voltage Correlation.
P0229 FAQ
What does P0229 mean?
P0229 means the PCM/ECM has detected an intermittent malfunction in the Throttle/Pedal Position Sensor/Switch C circuit.
Is P0229 a generic code?
Yes. P0229 is a Generic OBD-II Powertrain code, although the exact sensor and circuit configuration vary by manufacturer.
Where is the P0229 sensor located?
Depending on the vehicle, the relevant sensor may be integrated into the electronic throttle body or accelerator-pedal assembly.
What does the C mean in P0229?
The C identifies a designated throttle or pedal position signal circuit. It does not identify one universal physical sensor location.
Does P0229 mean the throttle body is bad?
No. Wiring, connectors, terminals, reference voltage, sensor ground and the accelerator-pedal assembly can also cause an intermittent P0229.
Can a loose connector cause P0229?
Yes. A loose or corroded connector can cause intermittent loss of the sensor signal.
Can a broken wire cause P0229?
Yes. An internally broken or damaged wire can intermittently open as the harness moves.
Can P0229 cause limp mode?
Yes. Some vehicles activate reduced-power or fail-safe operation when throttle or pedal position information becomes unreliable.
Can P0229 cause poor acceleration?
Yes. Intermittent signal loss can cause hesitation, delayed throttle response or reduced engine power.
How do you find an intermittent P0229?
Monitor live data while inspecting the harness and connectors. A wiggle test and oscilloscope can be especially useful for capturing intermittent signal failures.
Should I replace the throttle body immediately?
No. Inspect and test the wiring, connectors, reference, ground and signal circuit before replacing the throttle body.
Can an oscilloscope help diagnose P0229?
Yes. An oscilloscope can capture brief dropouts, spikes and signal disturbances that may be missed by a scan tool.
Final Takeaway
P0229 indicates an intermittent malfunction in the Throttle/Pedal Position Sensor/Switch C circuit.
Because intermittent faults can disappear temporarily, connector and wiring inspection is especially important. A loose terminal, damaged wire, corrosion, poor ground, unstable reference voltage or failing position sensor can all produce the code.
Because the implementation of sensor C varies between manufacturers, always identify the exact component and circuit using the vehicle-specific wiring diagram and service information.
Do not replace the throttle body, accelerator pedal or PCM simply because P0229 is stored. Confirm the intermittent fault through testing first.