What it means
The high-voltage service disconnect circuit reports a circuit 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 is a safety device that separates the traction battery from the vehicle's high-voltage system for service. The control module monitors its low-voltage circuit to confirm the disconnect state, and this code means the circuit reports a fault that prevents the module from verifying that state.
Common causes
Most likely first.
- Service disconnect switch failed
- Wiring fault
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 scan for related hybrid-system codes to see whether the fault appeared during startup, service, or operation.
- Check the owner's manual procedure and visually confirm that the service disconnect is fully seated in its normal operating position; do not remove or handle it.
- With the vehicle powered down, inspect accessible low-voltage wiring and connectors for the service disconnect circuit for damage, looseness, or corrosion.
- Use the vehicle's wiring information and manufacturer's procedure to test the low-voltage disconnect switch circuit for continuity and connection faults.
- If the circuit wiring is intact, have the service disconnect switch tested or replaced by a qualified hybrid technician.
Common fixes
- Correct an incompletely seated service disconnect only as directed in the owner's manual.
- Repair damaged or loose low-voltage wiring or connector terminals in the disconnect circuit.
- Replace a failed service disconnect switch after confirming the circuit fault.
- Clear the code and verify that the vehicle recognizes the disconnect state 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 limited; arrange safe transport for diagnosis. The fault means the system cannot verify a high-voltage safety state, so do not remove the disconnect or work on high-voltage parts.
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.