Advanced Diagnostics

Advanced Diagnostics - DTC P0A27 (46): High Voltage Contactor/Bypass Contactor Stays Activated






General Description
When the ignition switch is turned to LOCK (0) while the integrated motor assist (IMA) system is in an idle stop condition, the high voltage contactor opens and the stored charge in the power drive unit (PDU) capacitor which is built into the motor power inverter (MPI) module, is consumed by the DC-DC converter and lowers the MPI module voltage. But if there is a high voltage contactor turn-on failure, the discharge mentioned above is impossible. Therefore, when the difference between the MPI module voltage value before the high voltage contactor opening process and the MPI module voltage value after the high voltage contactor opening process does not change for a specified duration, a high voltage contactor turn-on failure is detected and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
The difference of the MPI module voltage before the high voltage contactor opening process and the MPI module voltage after the high voltage contactor opening process is 2.93 V or less for at least 10 seconds.

Driving Pattern
1. Turn the ignition switch to ON (II).
2. Turn the ignition switch to LOCK (0), and wait for at least 15 seconds.
3. Turn the ignition switch to ON (II).

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the MCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.