OBD-II code family
Oxygen Sensor Reference Voltage Circuit Faults (8 codes)
8 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P2243O2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 1)
- P2244O2 Sensor Reference Voltage Performance (Bank 1 Sensor 1)
- P2245O2 Sensor Reference Voltage Circuit Low (Bank 1 Sensor 1)
- P2246O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 1)
- P2247O2 Sensor Reference Voltage Circuit/Open (Bank 2 Sensor 1)
- P2248O2 Sensor Reference Voltage Performance (Bank 2 Sensor 1)
- P2249O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
- P2250O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 1)
What these codes mean
These eight codes distinguish four reference-voltage conditions at two sensor positions. Bank 1 Sensor 1 uses P2243 circuit/open, P2244 performance, P2245 low and P2246 high. Bank 2 Sensor 1 uses P2247 circuit/open, P2248 performance, P2249 low and P2250 high. Preserve both the position and condition when interpreting the full manufacturer report.
Reference in an oxygen-sensor title is not automatically the shared five-volt supply used by other engine sensors, or a chassis-ground return. The installed interface and wiring diagram determine the function. Bosch's LSU 4.9 datasheet separates virtual ground, pump current, Nernst voltage, heater and trim functions; Ford's covered 2024–2025 summary describes different reference and current paths for different interfaces.
An open label does not mean that every live value is a default or that continuity is the only useful test. The 2005 GM L66 table uses a sensor-cell response for its P2243/P2247 reference-open checks and separately maps P2245/P2249 to reference-short checks. The procedure must establish which controlled relationship is meaningful on the actual vehicle.
Performance does not guarantee that all readings stayed within their absolute limits or that the wiring is intact. The archived Mitsubishi 2008 Lancer X P2244 entry uses a circuit-voltage judgement and includes sensor and harness alternatives. A current normal display cannot disprove an earlier event or certify a newly fitted part.
High also needs its application context. The archived Mitsubishi 2012 Outlander XL P2246 entry pairs its proportional-oxygen-sensor reference-high heading with an oxygen-concentration judgement. This bounded example does not make every P2246 a mixture fault, but it prevents treating the generic label as universal proof of battery voltage on a shared supply or inevitable electronics damage.
A bank designation does not locate a connector, specify a harness length or predict labour. An unaffected comparison bank cannot clear a shared connection without the correct tests. Preserve companion pumping, heater, reference and mixture codes and note prior work or weather timing without turning those observations into cause rankings.
Have protected diagnosis distinguish the sensing assembly, connector, vehicle wiring and receiving interface. Do not unplug sensors with power applied, bridge a reference to ground, apply a generic resistance test, deliberately heat or cool components, manipulate live wiring or reproduce the event under road load. The applicable procedure determines safe isolation, capture and interpretation.
A repair estimate should follow a demonstrated fault and include the required verification. These conditions cannot guarantee fuel-control behaviour, completed readiness, inspection eligibility or a safe journey. Seek prompt symptom-based assistance for serious running changes, stalling or unreliable response.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.