What it means
The control module detects that the hybrid/EV battery negative contactor is stuck open.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The negative contactor is the high-voltage switch that connects the battery’s negative side to the drive system. The control module commands it to close and checks its state; this code sets when it remains open despite the close command.
Common causes
Most likely first.
- Contactor fault
- Contactor wiring or control circuit fault
Symptoms
- Hybrid system warning light
- Hybrid/EV system may not operate normally
How to diagnose it
- Read hybrid-system codes and freeze-frame data to check for related battery, interlock, or contactor-control faults.
- Check whether the vehicle reaches ready mode and record any warning or loss of hybrid operation.
- With the vehicle safely powered down according to the manufacturer's service information, inspect the negative-contactor wiring and connectors for damage, corrosion, looseness, or overheating.
- Use scan-tool data during the prescribed check to compare the negative contactor close command with its reported state.
- Have a qualified hybrid technician test the negative contactor coil and control circuit against the manufacturer's specification; do not probe high-voltage terminals.
- If the command and coil circuit pass, test the contactor's switching and feedback path using the manufacturer’s procedure.
Common fixes
- Repair a loose or corroded negative-contactor connector.
- Repair an open or damaged wire in the negative contactor control circuit.
- Replace the negative contactor if it fails to close despite a correct command and passing coil circuit.
- Repair or replace the control module only if its command or feedback fails the specified checks.
Can I keep driving?
If the vehicle will not enter ready mode or hybrid drive is unavailable, stop driving and arrange qualified hybrid diagnosis or recovery. Do not attempt to access or close the high-voltage contactor yourself.
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.