Cylinder 1 Glow Plug Circuit
On diesels each cylinder has a glow plug that heats the chamber so the engine starts from cold.
What the car has detected
The ECU or glow plug relay does not see the right current in cylinder 1’s glow plug: it is usually burnt out or has a loose wire.
It is not dangerous, but in winter the car may be hard to start, smoke white at first and shake until it warms up. Have it checked before the cold weather.
Symptoms
- Engine warning light on
- Hard cold starting
- White smoke and a shaking engine at start-up
Possible causes
- Burnt-out glow plug
- Loose or corroded glow plug wire or connector
- Faulty glow plug relay or control unit
Checks for the garage
- Measure the glow plug resistance
- Check the glow plug wire and connector
- Test the glow plug relay
Next step
Ask for cylinder 1’s glow plug and its wire to be measured, and the others checked too.
You can keep using the car and book a visit without hurry. Removing a seized glow plug can snap it: better left to a garage.