P0D42: Battery Charger 14 Volt Output Voltage Sensor Circuit

What it means

A circuit fault is detected in the battery charger 14-volt output voltage sensor circuit. The reading may be unreliable.

At a glance

• The engine or gearbox may go into limp mode

How it works

The battery charger's 14-volt output voltage sensor reports the charger's low-voltage output to the control module. P0D42 indicates a circuit fault in that sensor circuit, so the module cannot rely on its output-voltage reading to manage charging.

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. Review freeze-frame data and live 14-volt output voltage sensor readings to determine whether the fault occurs during charging or is present continuously.
2. Inspect the 14-volt output voltage sensor connector and its wiring for loose connections, corrosion, or visible damage.
3. Check the sensor circuit's supply, ground, and signal paths against the vehicle wiring diagram and manufacturer's specification.
4. Test circuit continuity and check for shorts or opens using the manufacturer's procedure.
5. If the circuit and connectors pass inspection, test the 14-volt output voltage sensor and replace it only if it fails specification.

Common fixes

• Clean and secure a loose or corroded sensor connector.
• Repair an open, short, or damaged wire in the output voltage sensor circuit.
• Replace the 14-volt output voltage sensor if it fails testing.

Can I keep driving?

Charging may not start, may be interrupted, or may proceed more slowly, and the vehicle may limit charging functions. Avoid relying on normal charging until the fault is diagnosed, and heed any charging-system warning.