What it means
The negative contactor D of the battery charging system reports a control circuit low condition. HV charging path 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 control circuit for negative contactor D operates the switch in the high-voltage charging path. This code sets when the module detects a control-circuit signal that is lower than expected, which can result from a short to ground, a shorted coil, or resistance at the connector.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in contactor coil
- Connector pins corroded - high contact resistance
Symptoms
- Hybrid or EV system warning
- Charging may be disabled
- Vehicle may not start or enter Ready mode
How to diagnose it
- Check freeze-frame data and related codes to determine when the low signal occurred and whether the fault is isolated to contactor D.
- Use scan-tool data to compare the D contactor command and circuit status while the fault is active.
- With the vehicle safely powered down according to the manufacturer's procedure, inspect the D control wire and connector for grounding damage, corrosion, or bent terminals.
- Have a qualified technician test the control wire for a short to ground and measure the contactor D coil and connector resistance against the manufacturer's specification.
- If the wiring and coil pass, test the control-module output using the manufacturer's diagnostic procedure.
Common fixes
- Repair a control wire chafed or shorted to ground.
- Clean or repair corroded contactor D connector pins that are disrupting the circuit.
- Replace negative contactor D if its coil is shorted or out of specification.
- Repair the control-module output if circuit testing identifies it as the source of the low signal.
Can I keep driving?
Do not rely on charging until the warning is resolved, especially if the vehicle may not enter Ready mode. Avoid driving if a high-voltage warning or abnormal vehicle behaviour appears.
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.