Fuel Fired Heater Disabled
The fuel-fired auxiliary heater (used to warm coolant or DEF on cold start) has been disabled by the control module — typically because of repeated start failures, low-voltage supply, or a self-protection condition.
Affected components
- Fuel fired heater
- Heater glow plug
- Heater fuel pump
Common causes
- High likelihood: Heater glow plug failed
- Medium likelihood: Low battery voltage triggered lockout
- Medium likelihood: Fuel supply starved — empty tank or pump weak
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.