P0228 is a Generic OBD-II Powertrain code indicating that the PCM/ECM has detected a high input signal in the Throttle/Pedal Position Sensor/Switch C circuit.
The exact component represented by sensor C varies by vehicle. It may be integrated into the electronic throttle body or accelerator-pedal position assembly. The correct component, wiring, pinout and voltage specifications must always be confirmed using vehicle-specific service information.
What Does P0228 Mean?
P0228 means the PCM/ECM has detected that the electrical signal from the Throttle/Pedal Position Sensor/Switch C circuit is higher than the expected range.
The engine computer monitors throttle and accelerator-pedal position signals to determine driver demand and control engine torque. If the C signal becomes excessively high or remains above the permitted threshold, the PCM may store P0228 and activate a fail-safe or reduced-power strategy.
Is P0228 Generic or Manufacturer Specific?
P0228 is a Generic OBD-II Powertrain code. However, the actual sensor location, circuit design, connector, pinout, voltage range and diagnostic procedure vary between manufacturers.
What Is Sensor C?
Sensor C is a designated throttle or pedal position signal used by the engine-control system.
Depending on the vehicle, it may be integrated into:
- Electronic throttle body.
- Accelerator pedal assembly.
- Manufacturer-specific throttle/pedal position circuitry.
Modern electronic throttle systems commonly use multiple position signals so the PCM can compare them for plausibility and safety.
Where Is the P0228 Sensor Located?
If sensor C is part of the electronic throttle body, it is normally integrated into the throttle body mounted on the engine intake system.
If the C signal belongs to the accelerator-pedal position system, the 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?
P0228 does not identify the driver's or passenger's side. The letter C identifies a designated electrical sensor/signal circuit rather than a vehicle side.
Common Symptoms of P0228
- Check Engine Light.
- Reduced engine power.
- Limp-home mode.
- Poor throttle response.
- Hesitation during acceleration.
- Delayed accelerator response.
- Engine surging.
- Unstable acceleration.
- Possible stalling in severe cases.
Common Causes of P0228
- Throttle/pedal position sensor C fault.
- Signal circuit shorted to voltage.
- Damaged signal wiring.
- Incorrect or excessive sensor signal voltage.
- Reference-voltage problem.
- Connector damage.
- Loose connector terminals.
- Corroded terminals.
- Water intrusion.
- Damaged throttle body.
- Faulty accelerator-pedal assembly.
- Incorrect previous wiring repair.
- PCM/ECM fault, although this is less common.
Why Does P0228 Set?
The PCM continuously monitors the C position signal. When the signal exceeds the manufacturer's permitted upper threshold, the module can recognize a high-input condition and store P0228.
The sensor itself may be defective, but an electrical problem can produce the same result. For example, a signal wire shorted to a voltage source can make the PCM see an artificially high signal.
Typical Sensor C Signal
A functioning position sensor should produce a signal within the manufacturer's specified operating range and respond appropriately to throttle or accelerator-pedal movement.
There is no universal voltage value for P0228. Different manufacturers use different sensor designs and signal strategies. Always use the OEM specification for the exact vehicle.
How to Diagnose P0228
1. Scan the PCM
Use a professional scan tool to retrieve P0228 and record all stored, pending and related DTCs.
2. Check Freeze Frame Data
Review engine RPM, vehicle speed, throttle position, accelerator position, engine load and other available parameters when the code was recorded.
3. Check Live Data
Monitor the available throttle and accelerator-pedal position parameters.
Look for:
- Sensor C reading unusually high.
- Signal remaining fixed at an abnormal value.
- Incorrect correlation with other position signals.
- Position data that does not respond correctly.
- Unexpected changes during accelerator operation.
4. Compare Redundant Signals
If the vehicle uses multiple throttle or pedal position signals, compare their values and relationship.
A significant disagreement can indicate a sensor, wiring, connector or mechanical problem.
5. Inspect the Connector
Inspect the relevant connector for:
- Loose terminals.
- Corrosion.
- Water contamination.
- Damaged pins.
- Broken connector locks.
- Poor terminal contact.
6. Inspect the Wiring
Look for damaged insulation, chafing, crushed wires, heat damage, previous repairs and wiring that may contact another voltage source.
7. Check Reference Voltage
Following the manufacturer's diagnostic procedure, verify that the sensor reference voltage is within specification.
An abnormal reference voltage can affect more than one sensor and should be investigated before replacing the position sensor.
8. Check Sensor Ground
A poor sensor ground can cause incorrect sensor readings and may be accompanied by additional sensor-related DTCs.
9. Check for a Short to Voltage
Because P0228 is a high-input code, inspect the signal circuit for an unintended connection to a voltage source according to the manufacturer's test procedure.
10. Test the Signal Circuit
Use the vehicle-specific wiring diagram to identify the C signal circuit and test it according to OEM procedures.
Do not assume that wire colors or connector pin numbers are the same on Dodge, Toyota, Mazda, BMW, Ford, GM or other manufacturers.
11. Evaluate the Sensor or Assembly
If the wiring, connector, reference and ground are correct but the C signal remains abnormally high, the integrated throttle-body or accelerator-pedal sensor may be defective.
12. Clear and Retest
After repairing the confirmed cause, clear P0228 and perform a complete functional and road-test verification while monitoring the relevant position signals.
Oscilloscope Diagnosis
An automotive oscilloscope can help identify a continuously high signal, abnormal spikes, signal distortion or an electrical short that may not be obvious from basic scan-tool data.
────╱╱╱╱╱╱────
High Signal:
────────╱╱╱╱───
Short-to-Voltage Example:
════════════════
The exact waveform amplitude and operating range depend on the vehicle's sensor design.
P0228 vs P0225, P0226 and P0227
- 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.
The defining characteristic of P0228 is that the C circuit signal is detected as too high by the PCM.
Can a Short to Voltage Cause P0228?
Yes. A signal wire unintentionally connected to a voltage source can cause the PCM to detect an excessively high input.
Can a Bad Reference Voltage Cause P0228?
Yes. An abnormal reference circuit can alter the sensor output. The reference circuit should be tested according to the vehicle-specific diagnostic procedure.
Can the Throttle Body Cause P0228?
Yes. If the C position sensor is integrated into the electronic throttle body, an internal sensor or circuit fault can produce P0228.
Can the Accelerator Pedal Cause P0228?
Yes, depending on the vehicle. If the relevant C signal is part of the accelerator-pedal position system, a defective pedal sensor or assembly can cause the code.
Can a Weak Battery Cause P0228?
Low system voltage is not the typical direct cause of a high-input code, although unstable electrical supply can contribute to electronic-control faults on some vehicles. A persistent P0228 should be diagnosed at the circuit level.
Can a Dirty Throttle Body Cause P0228?
A dirty throttle body can cause mechanical throttle problems, but contamination alone does not normally prove a high electrical sensor signal. Test the electrical circuit before replacing components.
Is P0228 Serious?
P0228 can be serious. The throttle and accelerator position system is important for engine torque control. The PCM may reduce engine power or activate a fail-safe strategy when it detects an abnormal signal.
Can You Drive With P0228?
The vehicle may continue running, but throttle response can be limited or unpredictable. If the vehicle enters limp mode, loses acceleration or shows severe drivability problems, it should be diagnosed before continued driving.
Possible Repairs
- Repair a signal wire short to voltage.
- Repair damaged wiring.
- Repair connector terminals.
- Correct an abnormal reference-voltage condition.
- 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 signal circuit.
- Replacing the accelerator pedal without checking wiring.
- Assuming sensor C has the same location on every vehicle.
- Ignoring a possible short to voltage.
- Ignoring the reference-voltage circuit.
- Ignoring sensor ground.
- Using universal voltage specifications.
- Replacing the PCM too early.
- Clearing the code without verifying the repair.
Recommended Diagnostic Tools
- Professional OBD-II scan tool.
- Bi-directional diagnostic scanner.
- Digital multimeter for approved low-voltage circuit tests.
- Automotive oscilloscope.
- OEM wiring diagrams.
- Manufacturer-specific service information.
Related 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.
- P2135 – Throttle/Pedal Position Sensor A/B Voltage Correlation.
P0228 FAQ
What does P0228 mean?
P0228 means the PCM/ECM has detected a high input signal in the Throttle/Pedal Position Sensor/Switch C circuit.
Is P0228 a generic code?
Yes. P0228 is a Generic OBD-II Powertrain code, although the actual sensor and circuit configuration vary by manufacturer.
Where is the P0228 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 P0228?
The C identifies a designated throttle or pedal position signal circuit. It does not specify one universal physical location.
Does P0228 mean the throttle body is bad?
No. A short to voltage, wiring fault, connector problem, reference-voltage problem, ground fault or accelerator-pedal problem can also cause P0228.
Can a short to voltage cause P0228?
Yes. An unintended connection between the C signal circuit and a voltage source can produce a high-input condition.
Can P0228 cause limp mode?
Yes. Some vehicles activate reduced-power or fail-safe operation when the throttle or pedal position signal is outside the permitted range.
Can P0228 cause poor acceleration?
Yes. The vehicle may experience hesitation, limited throttle response, reduced engine power or unstable acceleration.
Can a damaged wire cause P0228?
Yes. Damaged insulation or an incorrectly repaired harness can allow the signal circuit to contact another voltage source.
Should I replace the throttle body immediately?
No. Check the wiring, connector, reference voltage, ground and signal circuit before replacing the throttle body.
Can an oscilloscope help diagnose P0228?
Yes. An oscilloscope can reveal high signal levels, spikes, electrical noise and abnormal waveform behavior that may not be obvious from scan-tool data.
Final Takeaway
P0228 indicates a high-input condition in the Throttle/Pedal Position Sensor/Switch C circuit.
The fault can originate from the sensor itself, but a short to voltage, damaged wiring, connector problem, reference-voltage fault, ground problem, throttle-body fault or accelerator-pedal fault can produce the same code.
Because sensor C is implemented differently between manufacturers, always identify the exact component and circuit using the vehicle-specific wiring diagram and service information.
Confirm the electrical cause before replacing the throttle body, accelerator pedal or PCM.