What it means
The control circuit of the HV battery negative contactor reports a control circuit high condition. HV main switching 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
The negative contactor connects the battery pack to the high-voltage system when commanded. P0AE0 sets when its control circuit signal is higher than expected, which can result from a wire shorted to battery positive or an open contactor coil. The control module may not be able to switch the pack reliably.
Common causes
Most likely first.
- Control wire shorted to B+
- Open contactor coil
- Connector pins corroded - high contact resistance
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 the negative-contactor command and circuit status to establish when the high condition appears.
- With the vehicle safely powered down, inspect the negative-contactor harness for damage, contact with power wiring, and corrosion or loose pins at the connector.
- Test the control wire for a short to battery positive according to the manufacturer's procedure.
- Measure contactor-coil continuity and resistance against the manufacturer's specification to check for an open coil.
- If the harness and coil pass, compare commanded and reported negative-contactor operation with a capable scan tool and trace the control circuit.
Common fixes
- Clean and secure corroded or loose connector pins.
- Repair a control wire shorted to battery positive or a damaged harness section.
- Replace the negative contactor if its coil is open or outside specification.
- Repair the control module connection or circuit if testing identifies it as the source.
Can I keep driving?
Limit driving and avoid long trips; reduced power, limp mode, or failure to enter Ready mode may leave you without normal propulsion. Seek prompt diagnosis because high-voltage switching and charging may be unreliable.
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.