P1133 — 17 documented meanings by make
Documented by: AUDI, BMW, CHEVROLET (DAEWOO), CHEVROLET (USA), CITROEN, FORD, HONDA, ISUZU, JAGUAR, LEXUS, MAZDA, OPEL / VAUXHALL, PEUGEOT, PORSCHE, SAAB, SEAT, SKODA, SUBARU, TOYOTA, VOLKSWAGEN, VOLVO — the meaning can differ between manufacturers
P1133 does not mean the same thing on every car — manufacturers reuse the number for different faults. 21 makes document it: Audi, BMW, Chevrolet (Daewoo), Chevrolet (USA), Citroen, Ford, Honda, Isuzu, Jaguar, Lexus, Mazda, Opel / Vauxhall, Peugeot, Porsche, Saab, SEAT, Skoda, Subaru, Toyota, Volkswagen, Volvo. Find your make below.
| Make | Documented meaning | Points at |
|---|---|---|
| Audi | Oxygen sensor heating circuit, bank 1 and 2 sensor 1, electrical failure | oxygen sensor |
| SEAT | Oxygen sensor heating circuit, bank 1 and 2 sensor 1, electrical failure | oxygen sensor |
| Skoda | Oxygen sensor heating circuit, bank 1 and 2 sensor 1, electrical failure | oxygen sensor |
| Volkswagen | Oxygen sensor heating circuit, bank 1 and 2 sensor 1, electrical failure | oxygen sensor |
| BMW | Oxygen sensor heater control circuit, bank 2 sensor 1 | oxygen sensor |
| Chevrolet (Daewoo) | Front heated oxygen sensor, HO2S1 too few transitions | oxygen sensor |
| Chevrolet (USA) | Front heated oxygen sensor, HO2S1 too few transitions | oxygen sensor |
| Citroen | Throttle valve position, track 1, pressure incoherence: | |
| Citroen | MAP sensor/mass air-flow meter correlation with throttle position sensor | manifold pressure sensor · correlation |
| Ford | Bank 1, fuel control shifted lean (FAOSC) | transmission |
| Mazda | Bank 1, fuel control shifted lean (FAOSC) | transmission |
| Honda | Heated oxygen sensor insufficient switching, bank 1 sensor 1 | oxygen sensor |
| Isuzu | Heated oxygen sensor insufficient switching, bank 1 sensor 1 | oxygen sensor |
| Jaguar | Bank 1, fuel control shifted lean | transmission |
| Lexus | Air fuel ratio sensor circuit response malfunction, bank 1 sensor 1 | |
| Opel / Vauxhall | Oxygen sensor, transition switch time ratio, bank 1, sensor 1 | oxygen sensor |
| Opel / Vauxhall | Oxygen sensor, too few rich/lean and lean/rich switches, bank 1, sensor 1 | oxygen sensor |
| Peugeot | Throttle valve position, track nr. 1, pressure incoherence | |
| Porsche | Oxygen sensor adaptation lower load range, bank 2, above limit | oxygen sensor · signal too high |
| Saab | Oxygen sensor circuit, low voltage, sensor 1 | oxygen sensor · signal too low |
| Subaru | Oxygen sensor heater circuit malfunction (low) | oxygen sensor · signal too low |
| Toyota | Air fuel ratio sensor circuit response, bank 1 sensor 1 | |
| Volvo | Oxygen sensor front bank 1 | oxygen sensor |
P1133 on Audi, SEAT, Skoda, Volkswagen
On Audi, SEAT, Skoda, Volkswagen vehicles P1133 is documented as: Oxygen sensor heating circuit, bank 1 and 2 sensor 1, electrical failure. P1133 is stored when the ECU sees malfunction on oxygen sensor (bank 1, sensor 1). That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related Audi, SEAT, Skoda, Volkswagen codes:
P1133 on BMW
On BMW vehicles P1133 is documented as: Oxygen sensor heater control circuit, bank 2 sensor 1. P1133 points at oxygen sensor (bank 2, sensor 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related BMW codes:
P1133 on Chevrolet (Daewoo), Chevrolet (USA)
On Chevrolet (Daewoo), Chevrolet (USA) vehicles P1133 is documented as: Front heated oxygen sensor, HO2S1 too few transitions. P1133 points at oxygen sensor (front). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related Chevrolet (Daewoo), Chevrolet (USA) codes:
P1133 on Ford, Mazda
On Ford, Mazda vehicles P1133 is documented as: Bank 1, fuel control shifted lean (FAOSC). P1133 points at transmission (bank 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Related Ford, Mazda codes:
P1133 on Honda, Isuzu
On Honda, Isuzu vehicles P1133 is documented as: Heated oxygen sensor insufficient switching, bank 1 sensor 1. P1133 points at oxygen sensor (bank 1, sensor 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related Honda, Isuzu codes:
P1133 on Jaguar
On Jaguar vehicles P1133 is documented as: Bank 1, fuel control shifted lean. P1133 points at transmission (bank 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Related Jaguar codes:
P1133 on Lexus
On Lexus vehicles P1133 is documented as: Air fuel ratio sensor circuit response malfunction, bank 1 sensor 1. P1133 is stored when the ECU sees malfunction on the circuit named in the code (bank 1, sensor 1). That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: Wiring or connector fault in the circuit; Component failed electrically; Supply or ground problem feeding the circuit; Controlling module fault, though this is the least common of the four.
Check first, cheapest first:
- Read all stored codes — a general fault code is often the symptom of a more specific one
- Inspect the connector and wiring for the named component
- Check supply and ground at the component
- Measure the component against specification
- Replace the component once wiring and supply are ruled out
Related Lexus codes:
P1133 on Opel / Vauxhall
On Opel / Vauxhall vehicles P1133 is documented as: Oxygen sensor, transition switch time ratio, bank 1, sensor 1; Oxygen sensor, too few rich/lean and lean/rich switches, bank 1, sensor 1. P1133 points at oxygen sensor (bank 1, sensor 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related Opel / Vauxhall codes:
P1133 on Porsche
On Porsche vehicles P1133 is documented as: Oxygen sensor adaptation lower load range, bank 2, above limit. P1133 is stored when the ECU sees signal too high on oxygen sensor (bank 2). That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: Open ground for the sensor, letting the signal float up; Signal line shorted to a supply voltage; Sensor failed open, which the module reads as maximum; Connector fault interrupting the return path.
Check first, cheapest first:
- Read the live value and compare with what the conditions should produce
- Check the sensor ground continuity back to the module
- Unplug the sensor: if the reading changes, the wiring is intact and the sensor is suspect
- Inspect the connector for corrosion or a spread terminal
- Replace the sensor once ground and signal wiring are confirmed good
Related Porsche codes:
P1133 on Saab
On Saab vehicles P1133 is documented as: Oxygen sensor circuit, low voltage, sensor 1. P1133 is stored when the ECU sees signal too low on oxygen sensor (sensor 1). That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: High resistance in the supply or ground path, dragging the signal down; Corroded connector adding resistance the module reads as a low reading; Sensor drifted out of tolerance with age; Partial short to ground somewhere in the signal line.
Check first, cheapest first:
- Read the live value on a scanner and compare with a known-good reading
- Clean and re-seat the connector, then re-test before replacing anything
- Check the ground point for that circuit — a poor ground causes this far more often than a bad sensor
- Measure the sensor against specification with the connector back-probed
- Replace the sensor only once the wiring and ground have been ruled out
Related Saab codes:
P1133 on Subaru
On Subaru vehicles P1133 is documented as: Oxygen sensor heater circuit malfunction (low). P1133 is stored when the ECU sees signal too low on oxygen sensor. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: High resistance in the supply or ground path, dragging the signal down; Corroded connector adding resistance the module reads as a low reading; Sensor drifted out of tolerance with age; Partial short to ground somewhere in the signal line.
Check first, cheapest first:
- Read the live value on a scanner and compare with a known-good reading
- Clean and re-seat the connector, then re-test before replacing anything
- Check the ground point for that circuit — a poor ground causes this far more often than a bad sensor
- Measure the sensor against specification with the connector back-probed
- Replace the sensor only once the wiring and ground have been ruled out
Related Subaru codes:
P1133 on Volvo
On Volvo vehicles P1133 is documented as: Oxygen sensor front bank 1. P1133 points at oxygen sensor (bank 1, front). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Usually one of: Sensor aged and slow to respond; Heater element failed inside the sensor; Wiring or connector fault at the sensor; Exhaust leak near the sensor drawing in air; Engine genuinely running rich or lean.
Check first, cheapest first:
- Read the sensor's live trace — a lazy or flat signal identifies an aged sensor without removing anything
- Check for exhaust leaks upstream of the sensor
- Inspect the connector, which sits in a hot and exposed place and corrodes
- Measure the heater resistance against specification
- Replace the sensor once the exhaust and wiring are ruled out
Related Volvo codes:
Which one is yours
A generic OBD reader gives you the number, not which of these meanings your manufacturer assigned to it. To get to the specific one:
- Use a brand-specific scanner — VCDS for VAG, INPA or ISTA for BMW, XENTRY for Mercedes, Forscan for Ford. It shows the manufacturer's own text rather than the generic one.
- Read all stored codes together — the neighbouring ones usually point at which system is involved and narrow the list.
- Check freeze-frame data: the RPM, temperature and load at the moment it triggered indicate which system was active.
- If you have no brand scanner, tell me the make and model below and I will tell you which of these applies to your car.
Code family
P1xxx is manufacturer-specific code (VW/Audi, BMW, Mercedes, Toyota etc. have different meanings for the same code number).
Severity
Manufacturer-specific codes need a brand scanner (VCDS for VAG, INPA for BMW, STAR for Mercedes).
That is what holds for P1133 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.
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Code breakdown
Who makes these pages, and how
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The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
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