P0221: Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance. Meaning, possible symptoms and checks before repair.
Meaning, symptoms, causes and checks
The controller detects implausible range/performance for throttle/pedal position sensor or switch channel B. The letter identifies a manufacturer-defined circuit, not necessarily a separate part. Identify the application before interpreting a scan-tool percentage.
Affected system: Powertrain
Symptoms
- Delayed, limited or absent accelerator response.
- Engine warning light and possible limp mode; idle may become uneven.
Possible causes
- Signal dropouts, incorrect installation/calibration or a damaged sensor.
- Connector/wiring fault; mechanical binding if the sensor belongs to the throttle.
What to check
- Use the wiring diagram to identify channel B: throttle, pedal or switch; read accompanying faults on the other channels.
- Inspect channel B’s connector, terminals and harness; test reference supply and ground using the OEM pin assignment.
- Log channel B through its travel and compare its relationship with other channels against OEM data; equal values are not required.
- Check installation and mechanical travel after identifying the component; perform adaptation only when the repair procedure requires it.
- After repair, clear codes and recheck channel B under the original recorded conditions, following the manufacturer’s procedure.
Also written as: P0221-00, P022100, PO221 (some scan tools add the fault-type byte, e.g. -00).