P0EFC: Battery Charger A Input Voltage Sensor C Circuit

What it means

A fault has been detected in battery charger A input voltage sensor C circuit. The code does not specify whether the fault is an open, short, or other circuit problem.

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 report a charger input voltage-related signal to the control module. P0EFC indicates a fault in sensor C's circuit, but does not specify whether the cause is an open, short, sensor failure, or another circuit problem.

Common causes

Most likely first.

1. Sensor failed
2. 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

1. Record freeze-frame data and compare sensor C's live reading with other charger input data to establish when the fault appears.
2. With the vehicle safely powered down according to the manufacturer's procedure, inspect sensor C and its connector for damage, contamination, corrosion, or a loose connection.
3. Follow the sensor C wiring back through the accessible harness and look for chafing, pinched sections, or damaged terminals.
4. Check sensor C circuit continuity and its power/reference and ground connections using the manufacturer's procedure.
5. If the wiring and connections pass, test sensor C's output to determine whether the sensor has failed.

Common fixes

• Reseat sensor C's connector and clean corroded contacts.
• Repair damaged wiring or terminals in sensor C's circuit.
• Restore a poor power/reference or ground connection.
• Replace input voltage sensor C if circuit tests confirm the sensor has failed.

Can I keep driving?

The charger may not start, may interrupt charging, or may charge more slowly, and charging functions may be limited. Follow the vehicle's charging warnings and avoid relying on normal charging until the circuit fault is resolved.