DTC P0138 Or DTC P0140: Condition

DTC P0138 is set when with engine running closed loop mode, average output voltage during specified time is too high, or with engine running closed loop mode, minimum output voltage during specified time is too high. MIL is illuminated when ECM detects malfunction during 2 consecutive drive cycles.

DTC P0140 is set when with engine running closed loop mode, average output voltage during specified time is too low, or with engine running closed loop mode, minimum output voltage during specified time is too low. MIL is illuminated when ECM detects malfunction during 2 consecutive drive cycles.