Glow Plug Module Control Module Power Circuit High
The voltage at the glow plug control module supply line is above the upper threshold. Indicates wiring or charging-system overvoltage condition.
Affected components
- Glow plug control module
- Alternator
Common causes
- Medium likelihood: Charging system overvoltage
- Medium likelihood: Wiring shorted to battery
- Low likelihood: Connector pins corroded - high contact resistance
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.