Faulty throttle body or pedal position sensor B track (internal wear or failure); Signal wire shorted to ground or chafed wiring in the sensor circuit; Open circuit or high resistance in the 5V reference or signal wire; Corroded, loose or damaged connector terminals at the sensor or control unit; Dirty or carbon-fouled throttle body affecting the throttle plate movement and readings; Fault within the engine control unit sensor supply or input circuit.

P0222

Throttle/Pedal Position Sensor/Switch B Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

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

What it means

P0222 means the engine control unit has seen the signal voltage from throttle or pedal position sensor B fall below its expected range. Sensor B is normally the second, redundant track used to cross-check sensor A, so a low reading suggests a short to ground, an open circuit or a failing sensor. The control unit will usually limit engine power as a safeguard, and which sensor is 'B' depends on the model and engine.

Symptoms

Engine warning light on
Reduced power or limp-home mode
Poor or delayed throttle response
Unstable or high idle, or stalling
Engine will not rev above a set speed
Cruise control not working

Possible causes

Faulty throttle body or pedal position sensor B track (internal wear or failure)likely
Signal wire shorted to ground or chafed wiring in the sensor circuitlikely
Open circuit or high resistance in the 5V reference or signal wirepossible
Corroded, loose or damaged connector terminals at the sensor or control unitpossible
Dirty or carbon-fouled throttle body affecting the throttle plate movement and readingspossible
Fault within the engine control unit sensor supply or input circuitrare

How to diagnose

Read all stored and pending codes and note any related throttle, pedal or reference voltage codes, then review the freeze frame data.
Check the manufacturer's information to confirm whether sensor B is on the throttle body or the accelerator pedal for this model and engine.
Inspect the wiring and connectors for chafing, water ingress, corrosion, bent pins and poor terminal tension.
With live data, compare sensor A and sensor B readings through the full pedal or throttle sweep and look for dropouts, or B reading low or not tracking A.
Check the 5V reference, ground and signal voltages at the sensor connector against the specified values for the model.
Test the signal wire for short to ground and the reference and signal wires for continuity and resistance with the connector and control unit disconnected.
Inspect the throttle body for carbon build-up or sticking, and clean only as the manufacturer allows.
If the wiring and supply are sound, replace the suspect sensor or assembly and check whether the reading is corrected.

How to fix

Replace the faulty throttle body or accelerator pedal assembly, as the sensor is often not sold separately.
Repair or replace damaged wiring, correcting any short to ground or open circuit.
Clean or replace corroded or loose connector terminals and secure the connector properly.
Clean a fouled throttle body using the correct procedure, then carry out any throttle adaptation or relearn the manufacturer requires.
Only if all other causes are ruled out, diagnose the control unit and repair or replace it as advised by the manufacturer.

Can I keep driving?

Medium severity

The car may be driveable in limp-home mode, but power is limited and throttle response can be unpredictable, which is a risk in traffic. Get it fixed soon, and stop driving if it stalls or the throttle behaves erratically.

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