P06C4
Cylinder 12 Glow Plug Circuit Range or Performance
The glow plug on cylinder 12 is electrically intact yet does not heat to the calibrated temperature in the expected time - aged element, increased contact resistance, or a partially corroded ground.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Symptoms
- Glow plug warning light on (often orange coil symbol)
- Hard cold start or no start in cold weather
- White smoke from exhaust during warm-up
Common causes
Ordered by how often each turns out to be the cause.
- Plug element agedCommon
Parts involved
- Glow Plug Cyl 12
P06C4 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.