DTC P0AE4 (129)
DTC P0AE4 (129): HV Battery Precharge Contactor Control Circuit Open
General Description
In the electric powertrain system, the main contactor-positive is turned OFF and the main contactor-positive weld detection is performed when the vehicle condition is turned to the OFF (LOCK) mode or when the plug-in charge is stopped, or the system is stopped by fail safe action. Then, when the precharge contactor-positive is turned ON, the precharge operation causes the power drive unit (PDU) capacitor to be charged with electric charge and the Inverter voltage (charger DC end voltage) rises. In case of a precharge resistor disconnection failure, the Inverter voltage does not rise since the above-mentioned charging does not occur. When the vehicle condition is turned to the OFF (LOCK) mode in battery condition monitor module A, the voltage value is monitored by the Inverter voltage sensor, and when charging, by the charger ECU voltage sensor, and after turning ON, if the difference between the Inverter side voltage and the battery pack side voltage is out of a specified value after a specified time, the battery condition monitor module A 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 or after stop the Plug-in charge |
| Sequence | None |
| Duration | 400 milliseconds or more |
| DTC Type | One drive cycle, MIL off, POWER SYSTEM indicator on, 12 volt battery charging system indicator off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after precharge contactor on | 400 milliseconds | - |
| Battery condition monitor module A power-supply voltage | 10.2 V | - |
| Vehicle condition | Vehicle OFF (LOCK) mode, or Plug-in charge off, or Plug-in quick charge off | |
Malfunction Threshold
The difference between the battery pack voltage and the inverter voltage is more than 9.6 V for at least 600 milliseconds.
Possible Cause
- Main contactor A-negative CNT2(A) line open
- Main contactor B-negative CNT2(B) line open
- Precharge contactor A-positive PRE(A) line open
- Precharge contactor B-positive PRE(B) line open
- IGB relay IGHLDB/IG HOLD2 RLY CL- line open
- Bypass resistance poor connection
- Bus bar poor connection
- Junction board poor connection
- Main contactor A-negative stuck off
- Main contactor B-negative stuck off
- Precharge contactor A-positive stuck off
- Precharge contactor B-positive stuck off
- Service plug A failure
- Service plug B failure
- Inverter internal failure
- Battery charger internal failure
- DC-DC converter internal failure
- Battery condition monitor module A internal circuit failure
Confirmation Procedure
Operating Condition
- Turn the vehicle to the ON mode.
- Turn the vehicle to the OFF (LOCK) mode, and wait at least 220 seconds.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the POWER SYSTEM indicator comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the battery condition monitor module A memory.
Conditions for clearing the DTC
The POWER SYSTEM indicator is cleared if the malfunction does not return in next trip in which the diagnostic runs. The POWER SYSTEM indicator, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.