DTC P0AA1
DTC P0AA1: HV Battery Main Contactor Circuit Stuck Closed
General Description
In electric powertrain system, if the vehicle condition is turned to the OFF (LOCK) mode when the vehicle is in a stationary condition, or when electric powertrain system is stopped due to a fail safe action, the high voltage contactor turns OFF which was ON during the electric powertrain system was activated. If either the high voltage contactor or the high voltage sub contactor is turned OFF, the electric charge charged in the power drive unit (PDU) capacitor of the inverter is discharged by the DC-DC converter and the bypass resistor, and the inverter voltage drops. In case of an ON malfunction of the high voltage contactor, the voltage is not discharged so the inverter voltage does not drop. The battery condition monitor module monitors the voltage of the inverter voltage when vehicle condition is turned to the OFF (LOCK) mode, and if the voltage difference between the inverter voltage and the high voltage contactor voltage before and after turning OFF continues to be within a specified value for a certain period of time, the battery condition monitor module detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | After the vehicle condition is turned to the OFF (LOCK) mode |
| Sequence | None |
| Duration | 140 seconds or more |
| DTC Type | One drive cycle, MIL on, POWER SYSTEM indicator on, 12 VOLT CHARGING SYSTEM indicator on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Battery condition monitor module power-supply voltage | 10.2 V | - |
| MPI module voltage | 84.9 V | 323.1 V |
| Inverter voltage variability | - | 23.0 V |
| Vehicle | OFF (LOCK) mode | |
Malfunction Threshold
The voltage difference between the inverter voltage before and after turning the high voltage contactor OFF is 48 V or less for at least 140 seconds.
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- High voltage contactor CNTP line short
- High voltage contactor stuck on
- Bypass contactor stuck on
- Battery condition monitor module internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the battery condition monitor module memory.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool clear command or the battery condition monitor module reset.