Engine

P0228 — Throttle/Pedal Position Sensor "C" Circuit High Input

Severity: medium Drive with care, to a shop

What P0228 means

The engine control unit constantly monitors the signal voltage from the throttle position or accelerator pedal sensor (circuit "C"). P0228 sets when that voltage rises above the expected range. Common causes are a lost ground, a signal wire shorted to power, or a failed sensor. Because the data can't be trusted, the ECU often limits engine power.

Symptoms

  • Check engine light on
  • Reduced engine power
  • Sluggish acceleration or delayed pedal response
  • Erratic idle or stalling
  • Limp mode activation

Possible causes

  1. Failed throttle position sensor (TPS) or accelerator pedal position (APP) sensor
  2. Damaged wiring: open circuit, short, or corrosion
  3. Signal wire shorted to positive voltage
  4. Corroded or loose connector terminals
  5. Dirty or mechanically faulty throttle body
  6. ECU input fault or software error (rare)

How to diagnose

  1. Scan all codes and freeze frame data, noting other throttle or pedal sensor codes
  2. Inspect sensor connectors and harness for corrosion, chafing and loose pins
  3. Watch live data for the sensors while pressing and releasing the pedal; readings should change smoothly without jumps
  4. Use a multimeter to check the 5 V reference, ground and signal wire at the sensor connector
  5. Test the signal wire for a short to power and check for an open ground with the connector unplugged
  6. Inspect the throttle body for carbon buildup and check that the plate moves freely
  7. If wiring is good, test the sensor against specs or swap in a known good one, and suspect the ECU last

Common fixes

  • Replace the throttle position or pedal position sensor
  • Repair or replace damaged wiring and connectors
  • Clean the throttle body and perform a throttle relearn
  • Update the ECU software or replace the ECU (rare)

Questions and answers

What does P0228 mean?

It means the voltage on throttle or pedal position sensor circuit "C" is too high. The ECU treats the signal as unreliable and may limit engine power.

Can I drive with P0228?

Only for a short distance and with care. The engine may lose power or stall, which is risky in heavy traffic.

How do I clear P0228?

A scan tool can erase it, but the code will return unless the cause is fixed. Check the sensor, wiring and connectors first.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.