P0676: cylinder 6 glow circuit open-load evidence

P0676 identifies an open-load result for cylinder 6's glow output in this GM monitor. The hardware evaluates electrical integrity of the connected circuit, not fuel injection or cylinder contribution.

An open-load specification is not a component specification

The source describes detection at 200 kilohms and says the condition should not be detected below 16 ohms. It leaves the full behavior between those statements unspecified. A technician should not turn either value into a universal acceptable glow-plug resistance.

The result is filtered through ten failures among twenty samples at 100 ms intervals. Type B reporting and glow-lamp indication are listed, so a single isolated reading is not the complete reported-fault rule.

Establish an eligible operating interval

Monitoring requires engine running outside cranking, battery voltage in range, no glow-system supply fault and enabled diagnostics. The duty-cycle window is above 2.50% and below 97.50%. A quiet test while a supply fault inhibits the monitor does not demonstrate a healthy cylinder-6 path.

Verification should confirm the correct channel and normal loading with those gates satisfied. The code alone cannot distinguish a disconnected connection from an open element or controller-path fault. Use the vehicle-specific isolation procedure; this table provides no component location, plug-removal instruction or safe basis for direct battery application to the heating element.

Source and applicability

2025 GM 25OBDG04B diagnostic parameter tables; the cited monitor only. Vehicle, engine and calibration applicability must be confirmed separately. These tables describe detection logic, not a complete repair procedure or a component replacement verdict. gm-2025-04b, PDF page 1243.