What it means
The HV battery precharge contactor is stuck in the open position. DC-link cannot be precharged before main contactor closure.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The precharge contactor closes briefly so the battery can raise voltage on the high-voltage DC link before the main contactors connect the pack. P0AE3 sets when the control module detects that the precharge contactor has not closed when commanded. Without precharge, the DC link may not reach the required level and the vehicle may not enter Ready mode.
Common causes
Most likely first.
- Contactor mechanically failed open
- Contactor coil burnt out
- Carbon or debris buildup preventing free movement
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Read freeze-frame and live data for the precharge command and DC-link voltage to confirm whether voltage rises during the attempted sequence.
- With the vehicle safely powered down, inspect the precharge-contactor connector and harness for loose pins, corrosion, or damage.
- Check the precharge-contactor coil and control-circuit continuity and resistance against the manufacturer's specification.
- Use the vehicle's service procedure to verify whether the contactor receives its commanded control signal during precharge.
- If the signal and wiring are correct, test the contactor for mechanical failure and inspect the precharge path for an open component.
Common fixes
- Secure or clean a loose or corroded precharge-contactor connection.
- Repair an open or damaged control wire.
- Replace the precharge contactor if its coil is burnt out or the mechanism fails to close.
- Repair another confirmed open component in the precharge path.
Can I keep driving?
Do not count on the vehicle starting or providing normal power; the failed precharge sequence can prevent it from entering Ready mode. Arrange prompt hybrid-system diagnosis and avoid repeated start attempts.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.