Faulty throttle or accelerator pedal position sensor (sensor C track reading low); Damaged, chafed or shorted wiring in the signal circuit to earth; Corroded, loose or contaminated connector terminals at the sensor or control unit; Open circuit or high resistance in the 5 volt reference or signal wire; Faulty throttle body or throttle actuator assembly with integrated sensor; Internal fault in the engine control unit.

P0227

Throttle/Pedal Position Sensor/Switch C Circuit Low.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
27: FaultThe specific fault in that area

What it means

P0227 means the engine control unit has detected a low voltage signal from the throttle or pedal position sensor 'C' circuit. The signal has fallen below the expected range, which usually points to a short to earth, an open circuit or a failing sensor. Which physical sensor is labelled 'C' depends on the vehicle, so the exact location varies by model and engine.

Symptoms

Engine warning light on
Car goes into limp mode with reduced power
Poor or delayed throttle response
Unstable or high idle
Hesitation or stalling when pulling away
Cruise control not working

Possible causes

Faulty throttle or accelerator pedal position sensor (sensor C track reading low)likely
Damaged, chafed or shorted wiring in the signal circuit to earthlikely
Corroded, loose or contaminated connector terminals at the sensor or control unitlikely
Open circuit or high resistance in the 5 volt reference or signal wirepossible
Faulty throttle body or throttle actuator assembly with integrated sensorpossible
Internal fault in the engine control unitrare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting engine speed, load and throttle angle when the fault set
Check for related throttle or pedal codes, which help identify which sensor is circuit C on this model
Visually inspect the sensor, connector and wiring for damage, chafing, water ingress or corrosion
With the ignition on, watch live data for the throttle and pedal sensor values while moving the pedal slowly through its full range, looking for dropouts or low readings
Wiggle the harness and connectors while watching live data to reveal intermittent faults
Check the reference voltage, earth and signal voltage at the sensor connector against the manufacturer's specification
Test the signal wire for continuity and for short to earth with the control unit and sensor disconnected
Check the throttle body for sticking or heavy carbon build-up, following the model-specific procedure

How to fix

Repair or replace damaged wiring and fix any short to earth or open circuit
Clean or replace corroded or loose connector terminals
Replace the faulty accelerator pedal sensor or throttle body assembly as confirmed by testing
Clean a dirty throttle body only if the manufacturer allows it, then carry out any required throttle adaptation or relearn
Replace or repair the control unit only after wiring and sensors are proven good, and have it programmed as required

Can I keep driving?

High severity

Avoid driving where possible, as the car may lose power or respond unpredictably to the pedal, which is a safety risk in traffic. If you must move it, do so only a short distance to a safe place or workshop.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.