Common Symptoms
- Hard starting in cold weather
- Extended cranking time before engine starts
- White smoke from exhaust on cold start
- Rough idle immediately after cold start
- Check engine light or glow plug indicator illuminated
Most Likely Root Causes
- Failed cylinder 4 glow plug
- Open or short circuit in glow plug wiring harness
- Corroded or loose glow plug connector
- Failed glow plug control module or relay
- High resistance in glow plug circuit ground
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Component Location
Cylinder 4 glow plug is threaded into the cylinder head on the number 4 cylinder, typically accessed from the valve cover side.
Manufacturer Notes
Some diesel engines use individually controlled glow plugs while others use a shared power bus with individual ground circuits.
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