fault code guide
P0141: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
The heating element inside the rear oxygen sensor has stopped working properly. Your car will drive normally, but the engine computer cannot monitor the catalytic converter until the exhaust warms up.
How it shows up: The amber engine management light stays on steadily on your dashboard. You will rarely notice any change in how the car drives, and the fault code P0141 is read using an OBD scanner.
Updated 9 November 2026
Can I keep driving?
Service soon
The car is safe to drive, but leaving it unrepaired can mask other engine faults and will cause an MOT fail.
What to do right now
- 1Check whether the engine management light is steady or flashing; a flashing light means stop immediately.
- 2Notice if the car feels down on power, hesitates or smells unusually hot.
- 3If the car drives normally and the light stays steady amber, continue your journey and book a garage inspection soon.
Likely causes
Most likely first.
- Likely
Burnt-out oxygen sensor heater element
The internal electrical resistance wire inside the sensor breaks over time from thousands of heat cycles, leaving the circuit open.
- Possible
Damaged sensor wiring or melted harness
The downstream sensor sits beneath the car where road debris, water spray or contact with the hot exhaust pipe can cut or melt the wires.
- Possible
Corroded electrical connector
Road salt and moisture can enter the plug connector under the floorpan, corroding the pins and breaking electrical contact.
- Rare
Blown oxygen sensor heater fuse
A short circuit in the wiring can blow the shared fuse that powers the sensor heaters.
What you can check yourself
Park somewhere safe and level, engine off, before you start.
- 1
Confirm dashboard warning light status
Park safely and verify that the engine management light is glowing steady amber rather than flashing. A steady light confirms it is safe to complete your journey.
- 2
Check the oxygen sensor fuse
Turn the engine off and consult your handbook to find the engine bay fuse box. Locate the fuse labelled for oxygen sensors or engine management and inspect whether the metal strip inside is broken.
- 3
Inspect visible wiring underneath the car
Look under the vehicle after the exhaust has cooled completely. Find the sensor screwed into the exhaust pipe behind the catalytic converter and check if its wire is torn, snagged or resting against bare metal.
- 4
Check the wiring plug connector
If you can safely reach the sensor plug without jacking the car up, check that it is pushed firmly together and the locking clip is intact.
Rough cost to fix
Rough estimateTypical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. The total cost depends mainly on whether you choose a genuine manufacturer part or a reputable aftermarket sensor, as well as how easily the old sensor unthreads from a rusted exhaust.
Downstream oxygen sensor replacement
- Do it yourself
- €60–160£50–140 in the UK
- At a garage
- €140–280£120–240 in the UK
Oxygen sensor wiring or connector repair
- Do it yourself
- Garage job
- At a garage
- €80–170£70–150 in the UK
Blown heater circuit fuse replacement
- Do it yourself
- €2–10£2–8 in the UK
- At a garage
- €40–80£35–70 in the UK
When to go to a garage
- Book a garage visit if the engine management light stays on after checking the fuses.
- Seek professional help if the old sensor is seized tight into the exhaust pipe, as forcing it risks stripping the exhaust threads.
- Stop driving and call roadside assistance if the engine light starts flashing or the engine begins running roughly.
Questions drivers ask
Can I keep driving my car with fault code P0141?
Yes, you can usually drive normally for short periods. This sensor sits after the catalytic converter and only monitors emissions performance, so it does not control fuel mixture directly. However, having an active fault light prevents you from noticing any new, more serious engine problems.
Will P0141 cause my car to fail the NCT or MOT?
On the UK MOT, a glowing engine management light is an automatic fail for petrol cars first used from July 2003 and diesels from July 2008. On the Irish NCT, an engine light or emissions fault code alone produces an Advisory Pass, failing only if the exhaust emissions exceed standard test limits.
What is the difference between P0135 and P0141?
Both codes indicate an internal heater failure, but on different sensors. P0135 refers to Sensor 1, which sits upstream before the catalytic converter and controls the engine fuel mixture. P0141 refers to Sensor 2, which sits downstream after the converter to monitor emissions efficiency.
Will clearing the P0141 code fix the problem?
No, resetting the code with a diagnostic tool will only turn the light off temporarily. As soon as the engine computer runs its internal test on the next cold start and detects no electrical current in the heater, the code and light will return immediately.
Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.
The warning light you may see
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General guidance for most cars, not a diagnosis of yours. Details differ by make, model and year - check your handbook, and if in doubt, don't drive.