What it means
The ECM detects a range/performance 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 reports the coupler’s temperature so charging can be controlled safely. The control module sets this code when the sensor B reading is electrically plausible but falls outside the expected range or does not respond as expected, which can reflect sensor drift or displaced mounting.
Common causes
Most likely first.
- Sensor characteristic drifted
- Sensor mounting displaced
- Sensor element aged beyond calibration window
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Scan for charging-system codes and record freeze-frame data and sensor B’s reported temperature before charging conditions change.
- Inspect sensor B’s mounting and the coupler area for displacement, damage, or anything preventing the sensor from sensing the coupler correctly.
- Compare sensor B’s reading with ambient temperature and any other available temperature readings, looking for an implausible offset or poor response.
- Inspect sensor B’s connector and wiring for looseness or damage that could distort its reading, even if the circuit has no open or short code.
- Test sensor B’s temperature response and mounting against the manufacturer’s procedure to identify drift or a misplaced sensor.
Common fixes
- Secure or correctly reposition sensor B if it has shifted from its intended mounting.
- Repair a loose or damaged sensor B connector or wiring that affects the reading.
- Replace sensor B if its response is outside the manufacturer’s calibration specification.
- Clear the code and verify plausible temperature readings and normal charging.
Can I keep driving?
Avoid charging while the vehicle reports this temperature-sensing fault, since charging may be limited or interrupted. Driving may be possible if there are no other battery-system warnings; follow any vehicle warning to stop or limit operation.
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.