P0141 fault code: O2 Sensor Heater Circuit

Last updated · OBDCode UK editorial

Can I drive with P0141? — Drive with care

Drive with care while this heater-circuit code is stored. Treat a persistent engine management light seriously and have the fault confirmed before your MOT.

P0141 means “O2 Sensor Heater Circuit” — a fuel and air metering fault in the powertrain. Drive with care. The computer has flagged the heater circuit for bank 1 sensor 2 — the oxygen sensor after the catalyst. This is an electrical heater-circuit fault, not a misfire warning on its own.

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 We do not publish DIY repair or strip-down steps for this code on this page.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.

Hot systems

Never open a hot coolant cap — pressure can scald you. Exhaust and catalytic converter get hot enough to burn and ignite debris. Stay clear of electric fans; they can run after shut-off.

P01xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0141 mean?

P0141 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P01xx block, which covers fuel and air metering. The stored description is “O2 Sensor Heater Circuit”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

How to diagnose P0141 yourself

  1. Confirm P0141 and freeze-frame: Plug a basic OBD-II reader into the diagnostic socket with the car stationary. Record whether P0141 is current or pending, the freeze-frame coolant temperature, and every companion code. Stop if: The engine management light is flashing, the cabin smells of exhaust, or you feel dizzy — switch off and get fresh air.
    Generic driver footwell showing a broad OBD-II socket search zone and the usual 16-pin socket shape.
    Park safely and switch off before locating the socket. Its position varies, so use the vehicle handbook and never force or dismantle trim.
  2. Separate heater codes from catalyst codes: On the same scan, list any P0135, P0130, or P0420-family codes. Do not clear codes yet. Note whether only the downstream heater is stored. Stop if: You were about to replace parts from the code number alone, or to go under the car on a jack to reach sensor 2.
  3. Note system voltage on the scanner: If your reader shows battery or system voltage with ignition on, write down the figure. Look at the instrument cluster for a charging warning. Do not disconnect the battery. Stop if: You see damaged orange high-voltage cables, a leaking or swollen battery, or you would need to work under the vehicle.

Will P0141 fail an MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off.

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

These figures are copied from the MOT fail cohort for the certificate wording below. They are not a diagnosis of this car.

Certificate wording: “Oxygen sensor Emission control equipment fitted by the manufacturer missing, obviously modified or obviously defective”.

Of 748 Class 4 vehicles that failed a 2024 MOT on that wording, 0.13% (95% CI 0.0–0.8) failed on the same wording again in 2025. The not-tested gap versus control was 18.1 points.

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.
P0100Mass or Volume Air Flow Circuit P0101Mass or Volume Air Flow Circuit Range/Performance P0102Mass or Volume Air Flow Circuit Low Input P0103Mass or Volume Air Flow Circuit High Input P0104Mass or Volume Air Flow Circuit Intermittent P0105Manifold Absolute Pressure/Barometric Pressure Circuit P0106Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance P0107Manifold Absolute Pressure/Barometric Pressure Circuit Low Input

P0141 — quick answers

Is it safe to drive with P0141?

Drive with care. Drive with care while this heater-circuit code is stored. Treat a persistent engine management light seriously and have the fault confirmed before your MOT.

Can I fix P0141 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 P0141 fail my MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off.

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.