4+7
Ignitor circuit fault — failed ignitor or triggering circuitry
This code typically points to
- Open HSI
- Control trigger failure
- Wiring fault to ignitor
Next checks to confirm
- Verify ignitor warm-up occurs
- Ohm ignitor; replace if open
- Verify control output to ignitor circuit
Escalation
Watchguard / no ignition
Reset behavior
Clears after successful ignition sequence or manual interruption of demand.
Urgent
Fix now