P0221 — Throttle/Pedal Position Sensor B Range/Performance
Moderate severityWhat it means
P0221 is stored when the engine control unit sees a fault involving throttle/pedal position sensor B. Sensor B is the second, redundant throttle/pedal position signal that the control unit cross-checks against sensor A for safety. A “range/performance” fault means the value is present but implausible — it does not agree with other sensors or expected conditions.
Common symptoms
- Readings that drift or disagree with related sensors
- Reduced power or limp mode
- Hesitation or poor throttle response
- Unstable idle
Likely causes
- Drifting, contaminated or aged sensor
- A mechanical issue skewing the reading
- Worn position sensor or throttle body
- Connector or wiring fault on the B circuit
What to check first
- Cross-check the reading against related sensors in live data on a cold start
- Compare sensor A and B percentages in live data — they should track together
- Inspect the connector and wiring
Can you keep driving?
Because B is a safety-redundant signal, the car often drops to reduced power; have it checked promptly.
Scan, log and diagnose with MechanicAI
Plug a Bluetooth OBD2 adapter into your car and let MechanicAI turn raw data into answers:
- Scan, read and clear fault codes in seconds
- Inspect every sensor with live data
- Create instant logs and automatic trip records
- And above all — analyze it all with AI for the most likely cause and clear next steps.
Related codes
All information, explanations and guidance on this page are general preliminary information only. They are estimates and may be entirely wrong, incomplete or inaccurate, or may not apply to your vehicle at all. Never take any action based on this content alone — do not decide to keep driving, clear codes, replace parts, repair or otherwise work on your vehicle based only on what you read here. In every case, and for any final decision, you must consult qualified technical personnel (a professional mechanic, an authorized service centre or an engineer) and obtain their approval before acting. MechanicAI accepts no liability or responsibility whatsoever for any damage, fault, injury, loss or outcome that may arise — directly or indirectly — from using or relying on this information, for any reason and under any circumstances. By using this page you acknowledge and accept these terms.