P2278Heated oxygen sensor (H028) 3, bank 1/heated oxygen sensor (H028) 3, bank 2 - signals transposed
Generic (OBD-II) interpretation in the TuningBot DTC database.
P · PowertrainEmissionsOBD2
What P2278 means
P2278
Heated oxygen sensor (H028) 3, bank 1/heated oxygen sensor (H028) 3, bank 2 - signals transposed
Generic · emissions
Data confidence78%
The control module detected a fault associated with the Heated oxygen sensor (H028) 3, bank 1/heated oxygen sensor (H028) 3, bank 2 - signals transposed circuit or function; the stored code identifies the affected component rather than a single failure mode.
Symptoms
MIL illuminated
Possible increased fuel consumption
Possible unstable idle
Possible causes
Wiring
Recommended checks
Read live sensor voltage/current and heater status
Inspect wiring and connectors
Check for exhaust leaks near the sensor
Check fuel trim values for upstream mixture faults
Powertrain: engine, transmission and driveline systems.
2
Generic SAE-standard code: same meaning on every make.
278
Specific fault index within the subsystem.
Frequently asked questions about P2278
What does P2278 mean?
Heated oxygen sensor (H028) 3, bank 1/heated oxygen sensor (H028) 3, bank 2 - signals transposed. The control module detected a fault associated with the Heated oxygen sensor (H028) 3, bank 1/heated oxygen sensor (H028) 3, bank 2 - signals transposed circuit or function; the stored code identifies the affected component rather than a single failure mode.
Is P2278 generic or manufacturer-specific?
P2278 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P2278 at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry and, where the ECU needs it, corrects the checksum too. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.
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