OBD
P0679
Cylinder 9 Glow Plug Circuit/Open
What it means
P0679 means Cylinder 9 Glow Plug Circuit/Open.
Check these first
- A failed glow plug in cylinder 9
- An open feed wire to the glow plug
- Rust or corrosion in the glow plug connector
- A faulty glow plug relay
- A weak battery
What to do next
- Check the glow plug and its feed wire at cylinder 9
- Test the glow plug coil resistance
- Inspect the connector for rust or water
- Verify the relay clicks and passes voltage
- Replace the glow plug if the coil is open
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.