Lambda sensorsGeneric OBD-II codeUrgency: Garage soon
Code P0141: rear lambda sensor heater (bank 1, sensor 2)
P0141 means: malfunction of the oxygen sensor (lambda sensor) heater circuit, bank 1, sensor 2.[1][2][3][4] The engine ECU has detected an electrical fault in the heater circuit of the rear lambda sensor on bank 1, the one located after the catalytic converter (sensor 2). That heater is a resistor built into the sensor that brings it quickly up to operating temperature after starting: Autodoc Club puts the minimum at about 400 °C and Wikipedia mentions around 316 °C. According to Mechanic Base, the code is set when the sensor does not reach that temperature as quickly as expected.[2][5][6]
What code P0141 means
The engine ECU has detected an electrical fault in the heater circuit of the rear lambda sensor on bank 1, the one located after the catalytic converter (sensor 2). That heater is a resistor built into the sensor that brings it quickly up to operating temperature after starting: Autodoc Club puts the minimum at about 400 °C and Wikipedia mentions around 316 °C. According to Mechanic Base, the code is set when the sensor does not reach that temperature as quickly as expected.[2][5][6]
The rear sensor is used mainly to monitor the catalytic converter: its signal is compared with that of the front one to see whether the catalytic converter is working properly. That is why this fault is barely noticeable when driving: Carista sees no significant driveability problems and EricTheCarGuy says you are most likely not to notice any difference. Usually only the engine warning light comes on and the car may fail an emissions test.[1][2][4][6][7][8]
Heater codes are distinguished by bank and by sensor position: P0141 is the heater of sensor 2 on bank 1, P0135 that of sensor 1 on the same bank, and P0155 and P0161 are the equivalents for bank 2. In the 2011 Saab 9-5 workshop manual, P0141 is described as the heater performance of sensor 2 and its control circuit is P0036.[4][7][9]
It is a generic OBD-II code (it starts with P0), so it means the same on any brand; what changes from one car to another is the sensor, the resistance its heater should have and where the fuse is.[10]
Original definition (SAE J2012): O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)[1][2][3][4]
Causes of P0141
From most to least likely, according to the sources.
- 1Failed internal heater in the rear sensor: burnt-out element, internal short circuit or resistance that is too high. This is the cause the sources put first.[1][2][4][5][11]
- 2Damaged wiring or connectors: wires shorted to ground or cut, high resistance in the heater circuit, corroded connectors or melted terminals.[1][2][4][5][11][12]
- 3Blown sensor heater fuse.[1][2]
- 4Fault in the ECU's own control circuit, an uncommon cause.[1][2][4]
Symptoms
- Engine warning light (check engine light) on in the instrument cluster.[1][2][4][5][12]Engine warning light: faults that cause it
- Slightly higher consumption: Autodoc Club speaks of a noticeable increase; Carista and Mechanic Base, of a slight worsening.[1][2][5]Uses more fuel: faults that cause it
- It may fail an emissions test.[2][4]
- When driving, you normally notice nothing: there are no significant driveability symptoms.[1][7]
How to diagnose P0141
In order: from the most likely and cheapest to check to the most expensive.
- 1Read all stored codes with a diagnostic tool and make sure you know which sensor is which: sensor 2 on bank 1 is the second one in the exhaust, after the catalytic converter, not the front one.[2][7]
- 2Check the sensor heater fuse: it is the first step Carista gives and the quickest thing to check.[1][2]
- 3Inspect the sensor connector and wiring: corrosion, melted terminals, chafed, shorted or cut wires.[1][2][5][11][12]
- 4Disconnect the sensor and measure the resistance of its heater with a multimeter: an infinite reading indicates a burnt-out heater, and a low reading (EricTheCarGuy mentions less than 20 Ω; HELLA, between 2 and 14 Ω) indicates the element may be fine. Compare it with the value in your car's workshop manual.[7][8]
- 5Check that voltage reaches the heater circuit with the ignition on (if it does not, go back to the fuse) and that the engine ground is in good condition; if necessary, follow the pinpoint tests in the manufacturer's manual.[2][9][11]
- 6If the fuse, connector and wiring are fine and the heater is out of specification, replace the rear bank 1 sensor with the part number the manufacturer gives for your car.[1][5][12]
- 7If the sensor has the correct resistance and the wiring is fine, the fault may be in the output voltage of the ECU itself: EricTheCarGuy suggests checking it, and Carista and Mechanic Base mention the ECU as an uncommon cause. That diagnosis is a job for a workshop with the manufacturer's wiring diagrams.[1][2][7]
Can I keep driving with P0141?
Garage soon
The sources do not entirely agree and none says to stop the car. Carista classes it as low severity and sees no significant driveability problems; Autodoc Club says it is not especially serious or dangerous, but that it must be fixed before it leads to bigger failures; Mechanic Base rates it as medium severity: since there are hardly any symptoms it is common to keep driving with the code, but it warns that driving with maladjustments can end up damaging other parts; CarParts accepts that the car can keep running, but advises avoiding driving until the sensor is replaced. The prudent course is to repair it soon.[1][2][4][5]
Documented faults related to P0141
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)Yes, on the first units: Hyundai and Kia recalled 2016–2018 Ioniq and Niro hybrids and plug-in hybrids because the main relay that connects the high-voltage battery could come loose, overheat and, in the worst case, cause a fire.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireYes, this is the most documented hybrid system fault: the hydraulic actuator that engages the combustion engine with the hybrid assembly has had two recalls (2018 for a leak on the Niro and 2025 for moisture in its electronic board on the Niro, Ceed and XCeed PHEV), with a risk of short circuit and fire.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
What is the difference between P0141 and P0135?
It is the same heater fault, but on a different sensor. Heater codes are distinguished by bank and by sensor position: P0135 corresponds to the front sensor on bank 1 (sensor 1, the one closest to the engine, before the catalytic converter) and P0141 to the rear one on bank 1 (sensor 2, the next one in the exhaust, after the catalytic converter). On engines with two banks, the bank 2 sensors have other codes (P0155 and P0161). That is why it is worth identifying exactly which sensor it is before disconnecting or replacing anything.[3][4][7]
Does P0141 mean the catalytic converter is damaged?
No. P0141 points to the rear sensor's heater, not the catalytic converter. That sensor is used to monitor the catalytic converter, and its efficiency is flagged by other codes, such as P0420. Mechanic Base also warns that a faulty rear sensor can give a false catalytic converter alarm, so it is worth fixing P0141 and then checking whether P0420 still appears.[8][13]
Can I drive with code P0141?
The car keeps running and no source says to stop it, but they differ on how cautious to be: Carista and Autodoc Club see it as not very serious, Mechanic Base gives it medium severity and CarParts advises avoiding driving until the sensor is replaced. The prudent course is to repair it soon, before it causes bigger problems.[1][2][4][5]
Do I have to replace the rear sensor when I see P0141?
Not straight away. First the fuse, connector and wiring are checked, and the heater resistance is measured. The sensor is replaced when the heater is burnt out or out of specification and everything else is fine; if the heater is good and the wiring too, the fault may be in the ECU output and replacing the sensor would not fix it.[1][2][7]
Does P0141 mean the same on all brands?
Yes. Codes starting with P0 are generic OBD-II codes and have the same definition for all manufacturers. What changes from one car to another is the type of sensor, the resistance the heater should have and where the fuse is, details you need to look up in each model's workshop manual.[10]
Will I pass the MOT with code P0141?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[14]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P0141 Code: O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)Carista · Technical documentation · consulted 2 October 2026
- P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)Mechanic Base · Technical documentation · published 7 January 2023 · consulted 2 October 2026
- P0141 — O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)The Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- P0141 Code: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)CarParts.com · Technical documentation · published 9 May 2025 · consulted 2 October 2026
- Código OBD2 P0141: causas, síntomas y cómo corregirloAutodoc Club · Technical documentation · consulted 2 October 2026 · in Spanish
- Oxygen sensorWikipedia · Other source · consulted 2 October 2026
- P0141, P0135, P0147, P0155, P0161, P0167 02 Sensor Heater Circuit MalfunctionEricTheCarGuy · Other source · consulted 2 October 2026
- Lambda sensor - cause of failure, testing and troubleshootingHELLA (HELLA Tech World) · Manufacturer · consulted 2 October 2026
- DTC P0030, P0036, P0053, P0054, P0135 or P0141 (9-5 9650, 2011, 2.0 l petrol)Saab WIS Online (Saab Workshop Information System) · Technical documentation · consulted 2 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 2 October 2026
- P0141 OBD Error Code: Problem & SolutionsPartsAvatar · Technical documentation · published 2023 · consulted 2 October 2026
- 16525/P0141/000321 - Oxygen (Lambda) Sensor B1 S2; Heating Circuit: MalfunctionRoss-Tech Wiki · Technical documentation · consulted 2 October 2026
- P0420 – Catalyst System Efficiency Below Threshold (Bank 1)Mechanic Base · Technical documentation · published 7 November 2025 · consulted 2 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish