Throttle/Pedal Position Sensor/Switch C Circuit High Input
Code P0228 indicates the throttle position sensor or pedal position sensor circuit is reading abnormally high voltage to the PCM. This causes the engine to enter limp mode with severely restricted acceleration as a safety measure, since the computer cannot accurately determine driver intent.
What You Might Notice
- Severely limited or no engine acceleration
- Engine stalls at idle or during normal driving
- Stuck throttle position at any RPM
- Hesitation when attempting to accelerate
- Limp mode activation with reduced power output
Most Common Causes
- 1
Open or shorted throttle position sensor circuit
A break in the wiring harness between the TPS and PCM, or an internal short in the sensor, causes the high voltage signal. This is the most common cause of P0228.
- 2
Defective throttle position sensor or pedal position sensor
The TPS or PPS sensor has failed internally and is sending a constant high voltage signal instead of a variable one proportional to throttle opening.
- 3
Corroded or damaged electrical connectors
Corrosion, moisture, or loose connections at the TPS/PPS connector create high resistance or intermittent signal issues that the PCM interprets as high voltage.
- 4
Faulty drive-by-wire throttle actuator motor
On electronically controlled throttle systems, a defective actuator motor or its control circuit can produce abnormal voltage readings detected by the PCM.
How to Diagnose It
- 1
Check Open or shorted throttle position sensor circuit — A break in the wiring harness between the TPS and PCM, or an internal short in the sensor, causes the high voltage signal. This is the most common cause of P0228.
- 2
Check Defective throttle position sensor or pedal position sensor — The TPS or PPS sensor has failed internally and is sending a constant high voltage signal instead of a variable one proportional to throttle opening.
- 3
Check Corroded or damaged electrical connectors — Corrosion, moisture, or loose connections at the TPS/PPS connector create high resistance or intermittent signal issues that the PCM interprets as high voltage.
- 4
Check Faulty drive-by-wire throttle actuator motor — On electronically controlled throttle systems, a defective actuator motor or its control circuit can produce abnormal voltage readings detected by the PCM.
How to Fix It
- 1
Inspect and replace throttle position sensor
Disconnect the sensor connector and measure voltage with the key on and throttle at idle and wide open. If voltage is stuck high or erratic, replace the TPS with an OEM or quality aftermarket unit.
- 2
Check and repair throttle sensor wiring harness
Inspect the wiring between the TPS and PCM for breaks, pinches, or damage. Trace the circuit with a multimeter to verify continuity and proper voltage levels. Repair or replace damaged sections of wire.
- 3
Clean or replace corroded connectors
Disconnect the TPS connector and inspect for corrosion, moisture, or bent pins. Clean with electrical contact cleaner and dielectric grease, or replace the connector if severely damaged. Reconnect securely.
- 4
Inspect or replace drive-by-wire actuator
On electronic throttle systems, test the throttle actuator motor voltage and response. If the motor or its circuit board is faulty, replace the complete throttle body assembly as a unit to restore proper operation.
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