What does code P2A3C mean?

DTC codes / P2Axx · Hybrid propulsion / P2A3C

P2A3CO2 Sensor Negative Current Control Circuit Low Bank 1 Sensor 3

P2A3C indicates that the powertrain control module (PCM) has detected a low current condition on the negative control circuit for the downstream oxygen sensor on bank 1, sensor 3. This sensor is used to monitor oxygen storage efficiency after the catalytic converter, and the circuit's negative control is responsible for precisely regulating the sensor's pump current. The PCM sets this code when the current on that control wire falls below the expected threshold, which can be caused by a wiring fault, a failing sensor, or a PCM driver issue.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.