Glow plug light (diesel)
Also called: coil light, wait to start light
On a diesel: wait for it to go out before starting. Flashing means a fault.
What it means
On diesel engines the coil-shaped light means the glow plugs or intake heater are warming the engine for a cold start. Wait for it to go out, then crank. If it flashes or stays on while driving, the engine computer found a fault, and on some vehicles this light doubles as the engine fault light.
Green, yellow, red: three ways this can look
Match your situation to the closest example.
Keep an eye on it
It comes on briefly with the key on and goes out before you start. That's normal.
Schedule a repair
It stays on while driving or flashes. Get it scanned soon. It may be a glow plug circuit or a separate engine fault.
Stop and get help
Hard starts or no-start in the cold with the light flashing, or a power derate. Get help before the next cold morning strands you.
Common causes
- Normal pre-heat cycle
- Burned-out glow plug
- Glow plug module or relay
- Intake heater fault
- Other engine fault on some models
What to do right now
- Wait for the light to go out before cranking
- If it flashes or stays on while driving, have the codes read
Related guides
Symbols and meanings vary a little by make and model. Your owner's manual has the exact meaning for your vehicle.
Other warning lights
Questions
What does the glow plug light (diesel) mean?
On a diesel: wait for it to go out before starting. Flashing means a fault. On diesel engines the coil-shaped light means the glow plugs or intake heater are warming the engine for a cold start. Wait for it to go out, then crank. If it flashes or stays on while driving, the engine computer found a fault, and on some vehicles this light doubles as the engine fault light.
Can I keep driving with the glow plug light (diesel) on?
Green: It comes on briefly with the key on and goes out before you start. That's normal. Yellow: It stays on while driving or flashes. Get it scanned soon. It may be a glow plug circuit or a separate engine fault. Red: Hard starts or no-start in the cold with the light flashing, or a power derate. Get help before the next cold morning strands you.
What causes the glow plug light (diesel)?
Common causes: normal pre-heat cycle; burned-out glow plug; glow plug module or relay; intake heater fault.
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