P0221 fault code: Throttle/Pedal Position Sensor/Switch 'B' Circuit Range/Performance

Last updated · OBDCode UK editorial

Can I drive with P0221? — Drive with care

Treat this as a fault to get diagnosed soon, not as clearance for the journey. If the throttle is in limp home, keep speeds modest and stay off motorways while response is poor. Stop if the pedal and the car's actual speed disagree badly.

P0221 means “Throttle/Pedal Position Sensor/Switch 'B' Circuit Range/Performance” — a fuel and injector circuits fault in the powertrain. Drive with care. Sensor B’s position signal is out of the range the computer expects, or it does not track plausibly. That is a performance/range complaint on circuit B, not a low-voltage-only fault (that is P0222).

Can I DIY?

Caution — conditions apply. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage.

Caution — conditions applyDIY boundary
ToolsBasic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

Some checks may be possible for a careful DIY driver with the right tools and a safe place to work. Stop if anything feels beyond your skill or kit.

12V electrical safety

On a 12V battery: disconnect negative first, reconnect negative last. Prevent sparks and short circuits. Stop if the battery is damaged or sits near orange high-voltage cables.

P02xxFuel and injector circuits
MOT fail riskif the warning light stays on

What does P0221 mean?

P0221 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P02xx block, which covers fuel and injector circuits. The stored description is “Throttle/Pedal Position Sensor/Switch 'B' Circuit Range/Performance”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0221 fail an MOT?

A lit engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off. Limp-mode throttle faults still fail if the lamp is on.

Before booking your test, check what usually fails on your car: see our MOT pass rates by make and model, built from 33.1 million DVSA tests.

What the MOT data says

No MOT certificate item corresponds to this code; MOT outcome data cannot be shown.

Related guides

Car diagnostic test cost: compare the scopeUK booking marketplaces currently publish diagnostic averages of about £52–£65. Engine management light on: steady or flashing?A steady engine management light means the computer has stored a fault. Drive with caution and get the code read. A flashing light is different — stop when it is safe.
P0200Injector Circuit/Open P0201Injector Circuit/Open - Cylinder 1 P0202Injector Circuit/Open - Cylinder 2 P0203Injector Circuit/Open - Cylinder 3 P0204Injector Circuit/Open - Cylinder 4 P0205Injector Circuit/Open - Cylinder 5 P0206Injector Circuit/Open - Cylinder 6 P0207Injector Circuit/Open - Cylinder 7

P0221 — quick answers

Is it safe to drive with P0221?

Drive with care. Treat this as a fault to get diagnosed soon, not as clearance for the journey. If the throttle is in limp home, keep speeds modest and stay off motorways while response is poor. Stop if the pedal and the car's actual speed disagree badly.

Can I fix P0221 myself?

Caution — conditions apply. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage. Basic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

Will P0221 fail my MOT?

A lit engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off. Limp-mode throttle faults still fail if the lamp is on.

Fault-code identifiers are standard diagnostic facts. Their explanations and diagnostic guidance on this site are original editorial summaries, not reproduced SAE wording. MOT defect rules reflect the DVSA MOT inspection manual (2026). This page is general guidance for UK drivers, not a substitute for a professional diagnosis.