What it means
The ECM detects a circuit fault on the battery charger coupler temperature sensor b circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery charger coupler temperature sensor B measures temperature at the charging coupler so the vehicle can manage charging safely. The control module monitors sensor B’s circuit and sets this code when the circuit reading is faulty or unusable, which can prevent charging or cause it to be limited.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Scan the vehicle for charging-system codes and save freeze-frame data, including charge status and coupler temperature readings if available.
- With charging stopped and the vehicle made safe according to its owner information, inspect the coupler sensor B connector and visible wiring for damage, moisture, or loose terminals.
- Compare sensor B’s reported temperature with ambient conditions and other available temperature readings to see whether it is plausible.
- Use the wiring diagram to check sensor B circuit continuity and connector contact, following the manufacturer’s high-voltage safety procedures where applicable.
- Test sensor B and its circuit against the manufacturer’s specification to determine whether the sensor or wiring is at fault.
Common fixes
- Repair damaged wiring or loose connections in the coupler temperature sensor B circuit.
- Clean or repair corroded sensor B connector terminals and restore connector sealing.
- Replace coupler temperature sensor B if it fails the manufacturer’s circuit tests.
- Clear the fault and verify that charging starts and proceeds normally.
Can I keep driving?
Do not continue charging if the vehicle reports a charging or coupler temperature fault, or if the coupler is unusually hot or damaged. Driving may be possible, but charging can be unavailable or interrupted; follow the vehicle’s warning instructions.
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.