What it means
The control circuit B for the hybrid battery precharge contactor reports a high condition. Pre-charging the DC link before main contactor closure 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 hybrid or EV battery precharge contactor B control circuit operates the coil that helps safely bring the inverter's DC link voltage up before the main battery contactors close. The control module monitors circuit B for a voltage level above its expected range. That high condition can prevent reliable precharge control and may lead the module to limit hybrid or electric operation.
Common causes
Most likely first.
- Control wire shorted to power
- Contactor driver fault
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
- Use a scan tool to save freeze-frame data and check for related hybrid battery or contactor codes before clearing the fault.
- With the vehicle powered down using the manufacturer's safety procedure, inspect the precharge contactor B harness and connector for damaged insulation, loose pins, corrosion, or contact with a power feed.
- Check whether the fault returns under the manufacturer's enable conditions; note whether it is constant or intermittent.
- With the high-voltage system made safe as specified by the manufacturer, test circuit B for a short to power and inspect its connections and continuity.
- If the harness passes, use the manufacturer's diagnostic procedure to test the contactor driver and determine whether the control module output is stuck high.
Common fixes
- Repair circuit B wiring that is shorted to a power feed.
- Clean, secure, or repair damaged terminals at the precharge contactor B connector.
- Repair or replace a failed contactor driver if testing confirms the fault.
- Clear the code and verify that precharge and contactor operation are normal.
Can I keep driving?
Limit driving if the hybrid warning is on or power is reduced, because the vehicle may enter limp mode or fail to start, and charging may be affected. Arrange prompt diagnosis and avoid handling high-voltage parts unless qualified.
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.