Glow Plug/Heater Circuit "A"
Glow plug system malfunction affecting engine starting, particularly in cold conditions. Indicates a fault in the glow plug circuit or components.
What You Might Notice
- Wait to start indicator stays on longer than normal
- Difficult cold starts
- Solid illuminated glow plug warning light
- Rough idle after starting
- Extended cranking time in winter
Most Common Causes
- 1
Faulty glow plug
One or more glow plugs have failed and need replacement.
- 2
Glow plug wiring fault
Wiring open circuit, short to ground, or corroded connections in glow plug harness.
- 3
Glow plug controller failure
Control module unable to supply proper voltage or signal to glow plugs.
- 4
Open fuse or relay
Blown glow plug fuse or defective glow plug relay preventing system operation.
How to Diagnose It
- 1
Check Faulty glow plug — One or more glow plugs have failed and need replacement.
- 2
Check Glow plug wiring fault — Wiring open circuit, short to ground, or corroded connections in glow plug harness.
- 3
Check Glow plug controller failure — Control module unable to supply proper voltage or signal to glow plugs.
- 4
Check Open fuse or relay — Blown glow plug fuse or defective glow plug relay preventing system operation.
How to Fix It
- 1
- 2
Repair wiring and connectors
Inspect harness for damage, corrosion, or loose connections; repair or replace as needed.
- 3
Replace glow plug relay
Test and replace defective relay controlling glow plug operation.
- 4
Replace fuse or controller
Check fuse rating; replace blown fuse or reprogram/replace glow plug controller module.
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