What it means
The signal from the battery charger A input current sensor is outside the expected range or performance criteria. The reading may be unreliable.
At a glance
- The engine or gearbox may go into limp mode
How it works
Battery Charger A's input-current sensor measures current entering that charger and sends the reading to the control module. P0D39 sets when the signal is present but its value or response does not meet the module's expected range or performance criteria.
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
- Save freeze-frame data and compare live Battery Charger A input-current readings with charging status to identify when the value becomes implausible.
- Inspect the input-current sensor's mounting and alignment, since displacement can make its reading inaccurate even when the connector is attached.
- Check the sensor connector and wiring for corrosion, damage, or a poor connection that could distort the signal.
- Test the sensor circuit and compare its output with charger input-current data using the wiring diagram and manufacturer's specification.
- If the circuit and mounting are correct, test the sensor for drift or degradation using the approved procedure.
Common fixes
- Secure the input-current sensor in its specified position.
- Repair a poor connection or damaged wiring affecting the sensor signal.
- Replace a sensor that has drifted or no longer meets the manufacturer's specification.
- Confirm the code stays cleared during a charging session.
Can I keep driving?
Charging may be interrupted, delayed, or limited because the module cannot rely on Battery Charger A's input-current reading. Avoid planning around a full charge until charging completes normally and the warning is resolved.
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.