Glow Plug/Heater Circuit "A" Malfunction
The glow plug control module reports an electrical fault on circuit A — typically a single glow plug open-circuit, the relay failing, or wiring to the harness damaged. Diesel-specific; affects cold-start behaviour.
Affected components
- Glow plug
- Glow plug relay
- Glow plug control module
Common causes
- High likelihood: One or more glow plugs open-circuit
- Medium likelihood: Glow plug relay failed
- Low likelihood: Wiring/harness damage
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
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.