What it means
The ECM detects a high fault on the battery charger coupler temperature sensor a 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
The battery charger coupler temperature sensor A reports the temperature of the charging connection. This code sets when its signal is higher than the control module's expected range, as can happen with an open sensor circuit or a signal wire shorted to battery voltage.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Record freeze-frame data and compare sensor A's live reading with ambient temperature; a fixed extreme value can help identify a high-signal fault.
- Inspect the coupler sensor A connector and wiring for an unplugged connection, corrosion, broken conductors, or insulation damage.
- With the vehicle made safe according to its service information, check for an open in the sensor A circuit and a short from its signal wire to battery voltage.
- Test coupler temperature sensor A against the manufacturer's specification to determine whether the sensor itself is open.
- If the sensor and wiring pass, check the related input circuit and module readings using the vehicle's diagnostic information.
Common fixes
- Reconnect a loose sensor A connector and repair damaged wiring.
- Clean corroded connector pins and restore a sound connection.
- Repair a signal wire short to battery voltage or an open circuit.
- Replace coupler temperature sensor A if it tests open or out of specification.
Can I keep driving?
Charging may not start or may stop because the vehicle cannot trust the coupler temperature reading. Avoid continued charging if the coupler is hot, damaged, or smells overheated, and arrange diagnosis before relying on charging.
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.