What it means
The battery charger A input voltage sensor C signal is outside the expected range or does not behave as expected. The code does not establish that the reading is unusable 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 A uses input voltage sensor C to provide the control module with a charger input voltage-related signal. P0EFD sets when sensor C's reading is outside the expected range or does not respond as expected, even though the signal may still be usable for some control decisions.
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
- Record freeze-frame data and compare sensor C's live reading with charger input data during the conditions that set the code.
- Inspect sensor C's mounting and position for displacement that could make its reading inaccurate.
- Check sensor C's connector and wiring for damage, loose contact, or corrosion that could distort the signal.
- Compare sensor C's response as charging conditions change with the manufacturer's expected behavior and check its circuit connections.
- If mounting and wiring are sound, test sensor C for drift or a response outside the manufacturer's specification.
Common fixes
- Secure sensor C in its correct mounting position.
- Clean and reseat sensor C's connector or repair poor pin contact.
- Repair wiring or connection faults affecting sensor C's signal.
- Replace sensor C if testing confirms drift or an out-of-range response.
Can I keep driving?
Charging may be interrupted, slower than expected, or unavailable, and the control module may limit charging functions. Follow the vehicle's warnings and have the sensor checked before relying on normal 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.