P0D04

What it means

P0D04 is a generic code for plug-in hybrid and electric vehicles. It means the control unit saw an intermittent or erratic signal from the charging ventilation switch or circuit, which is part of the control pilot charging function. The signal dropped out, flickered or changed without a valid reason while charging was being set up or carried out. How the ventilation function is used depends on the model, so check the manufacturer's information for your vehicle.

Symptoms

• Charging starts and stops, or will not start at all
• Charging fault or plug warning message on the dash
• Malfunction or service warning light on
• Charge session ends early or is refused at some charge points
• Fault only appears now and then, often when moving the charge cable or in wet weather

Possible causes

• Damaged, corroded or loose connector or wiring in the ventilation switch or control pilot circuitlikely
• Moisture or dirt in the charge inlet or connectors causing an unstable signallikely
• Faulty ventilation switch or sensing component, if fitted on this modelpossible
• Worn or damaged charge cable or charge point giving a poor control pilot signalpossible
• Poor earth or low voltage supply to the charging control unitpossible
• Fault inside the charging control unit or outdated softwarerare

How to diagnose

1. Read all stored and pending codes and note freeze frame data, including when and under what conditions the fault set.
2. Check for related charging, communication or low-voltage battery codes, and deal with those first if present.
3. Try a different charge cable and a different charge point to rule out external equipment.
4. Inspect the charge inlet and its connector for water, dirt, corrosion, bent pins or heat marks.
5. Inspect the wiring and connectors in the ventilation switch and control pilot circuit, wiggling them while watching live data for dropouts.
6. Check the low-voltage battery condition and the earth and supply connections to the charging control unit.
7. Use the manufacturer's wiring diagram to test the switch and circuit for correct signal, resistance and continuity.
8. Check for software updates or technical bulletins for this model before replacing the control unit.

How to fix

• Repair or replace damaged wiring and clean or replace corroded connectors.
• Dry out and clean the charge inlet, and replace it if it is damaged or water has got in.
• Replace the ventilation switch or sensing component if it tests faulty.
• Replace a worn charge cable, or use a different charge point if the fault is on the supply side.
• Repair earth and supply faults, and renew a weak low-voltage battery.
• Update the control unit software if a bulletin covers this fault, and replace the unit only if confirmed faulty.

Can I keep driving?

Nearby codes

• P0D03GenericControl Pilot Charging Ventilation Switch Circuit High
• P0D05GenericControl Pilot Charging Ventilation Switch Stuck Off