What it means
The control circuit of the HV battery precharge contactor A reports a control circuit range/performance condition. Precharge sequence cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Precharge contactor A closes briefly to raise high-voltage DC-link voltage before the main contactors connect the battery. The control module monitors contactor A's control response, and P0AE5 sets when that response is outside the expected range or does not match the command. The precharge sequence may then be unreliable.
Common causes
Most likely first.
- Coil resistance drifted
- High-resistance contact
- Sensor element aged beyond calibration window
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
- Check freeze-frame and live data for contactor A's command, reported response, and DC-link voltage during the event.
- With the vehicle safely powered down, inspect contactor A's connector and harness for corrosion, looseness, heat damage, or pin problems.
- Measure contactor A coil resistance and control-circuit continuity against the manufacturer's specification.
- Check voltage drop across contactor A circuit connections while following the vehicle's service procedure to find high resistance.
- If wiring and coil measurements pass, compare commanded and reported contactor A operation with a capable scan tool and assess its feedback element.
Common fixes
- Clean and secure a corroded or loose contactor A connector.
- Repair damaged wiring or a high-resistance connection in contactor A's control circuit.
- Replace precharge contactor A if its coil or feedback element is outside specification.
- Repair the control module circuit if tests isolate the fault there.
Can I keep driving?
Avoid long or routine trips because reduced power, limp mode, or failure to enter Ready mode may occur if precharge is unreliable. Have the hybrid system checked promptly, especially if charging is affected.
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.