P2243: Oxygen sensor reference voltage circuit open (bank 1, sensor 1)
Electrical fault on the reference wire of the bank 1 wideband oxygen sensor. Usually the connector, a broken wire or the sensor itself.
| Code | P2243 |
|---|---|
| System | Engine and transmission |
| Group | P22xx, NOx sensors, oxygen sensors and emissions |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P2243 means
The wideband oxygen sensor ahead of the catalytic converter works by comparing against a reference voltage supplied by the ECU. This code means that reference circuit is open (broken) or out of range. Without it, the sensor cannot measure and the ECU is adjusting the mixture blind.
Most common causes
- Loose, dirty or corroded sensor connector
- Reference wire broken or burnt by the exhaust
- Faulty wideband oxygen sensor
- Chafed wiring inside the loom
- Fault in the ECU circuit (uncommon)
Symptoms
- Engine warning light on
- Higher fuel consumption
- Slightly rough idle
- Possible loss of response
Can you drive with P2243?
With care You can drive, but the mixture is not controlled properly: consumption goes up and the catalyst can be damaged over time. Get it fixed soon.
Open the bonnetthe in-depth explanation
How to check it
Look for damage to the sensor lead (melted, chafed or stretched) and make sure the connector is fully home and dry. If P2237 or other codes for the same sensor appear too, it is almost always the wiring or the sensor.
How to read and clear P2243 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P2243 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P223D The lambda sensor pumping current (bank 2) gives readings outside the normal
- P2240 The lambda sensor positive current control (bank 2
- P2241 The lambda sensor positive current control (bank 2
- P2242 The lambda sensor positive current control (bank 2
- P2244 The lambda sensor reference voltage (bank 1
- P2245 The lambda sensor reference voltage (bank 1, sensor 1) is below normal
- P2246 The lambda sensor reference voltage (bank 1, sensor 1) is above normal
- P2247 The lambda sensor reference voltage (bank 2
- P2200 NOx sensor circuit fault (bank 1)
- P2201 NOx sensor circuit range or performance problem (bank 1)
- P2227 Barometric pressure sensor A range or performance problem
- P2228 Barometric pressure sensor A circuit low
What does code P2243 mean?
The wideband oxygen sensor ahead of the catalytic converter works by comparing against a reference voltage supplied by the ECU. This code means that reference circuit is open (broken) or out of range. Without it, the sensor cannot measure and the ECU is adjusting the mixture blind.
Can you drive with P2243?
You can drive, but the mixture is not controlled properly: consumption goes up and the catalyst can be damaged over time. Get it fixed soon.
How do you clear P2243?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P2243 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
