What it means
The high-voltage service disconnect circuit reports a circuit low condition. Safe HV disconnection state cannot be verified.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The high-voltage service disconnect's low-voltage monitoring circuit lets the control module verify the disconnect state before allowing hybrid operation. This code sets when that circuit signal is lower than expected, which can result from a wire shorted to ground, a shorted switch, or poor connector contact.
Common causes
Most likely first.
- Wire shorted to ground
- Switch shorted
- Connector pins corroded - high contact resistance
Symptoms
- Hybrid-system warning light may illuminate
- Vehicle may limit or disable hybrid operation
- Vehicle may fail to enter or remain in ready mode
How to diagnose it
- Record freeze-frame data and related hybrid codes to determine whether the low circuit reading appeared during startup or while the vehicle was operating.
- Confirm from the owner's manual that the service disconnect is in its normal operating position; do not remove or handle it.
- With the vehicle powered down, visually inspect accessible low-voltage disconnect-circuit wiring for chafing to ground and connectors for corrosion or damaged pins.
- Use the manufacturer's wiring diagram and test procedure to check the monitoring circuit for a short to ground and verify the switch signal.
- If the wiring is not shorted, have a qualified hybrid technician test the disconnect switch and connector contact condition.
Common fixes
- Repair a low-voltage disconnect-circuit wire shorted to ground.
- Clean or repair corroded connector pins or poor terminal contact.
- Replace a service disconnect switch confirmed to be shorted.
- Verify the circuit signal and clear the code after repair.
Can I keep driving?
Do not drive if the vehicle will not enter or remain in ready mode or if hybrid operation is disabled; arrange safe transport. The control module cannot verify the disconnect safety state, so do not handle the service disconnect or high-voltage wiring.
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.