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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 79 (HVAC - Manual) >> Diagnostic Information and Procedures >> DTC B0465, B0467, or B0478 >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition OFF, disconnect the harness connector at the combustion sensor.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the coolant heater.
  3. Ignition ON, verify the scan tool Flame Temperature Sensor parameter is greater than 4.5 volts.
    • If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the coolant heater.
  4. Install a 3A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool Flame Temperature Sensor parameter is less than 0.5 volts.
    • If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the coolant heater.
  5. If all circuits test normal, test or replace the combustion sensor.
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