What it means
The control circuit of the HV battery precharge contactor A reports a control circuit high 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 temporarily to charge the high-voltage DC link before the main contactors connect the battery. P0AE7 sets when the control module detects a signal higher than expected in contactor A's control circuit, which may be caused by a short to battery positive or an open coil. The precharge sequence may not operate 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 contactor A's command and circuit status to establish when the high condition appears.
- With the vehicle safely powered down, inspect contactor A's harness for damage, contact with power wiring, and corrosion or loose connector pins.
- Test contactor A's control wire for a short to battery positive according to the manufacturer's procedure.
- Measure contactor A 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 contactor A operation with a capable scan tool and trace the control circuit.
Common fixes
- Clean and secure corroded or loose contactor A connector pins.
- Repair contactor A's control wire if it is shorted to battery positive.
- Replace precharge contactor A if its coil is open or outside specification.
- Repair the control module circuit if testing confirms it is the source.
Can I keep driving?
Limit driving and avoid long trips because reduced power, limp mode, or failure to enter Ready mode may occur when contactor A cannot be controlled properly. Seek prompt diagnosis because precharge 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.