Page 1 of 8 P0030 - O2 SENSOR 1/1 HEATER CIRCUIT
Page 2 of 8 For a complete wiring diagram Refer to Section 8W
Page 3 of 8 When Monitored: With the ignition on and the Oxygen Sensor Heater command on. Set Condition: The ECM detects an implausible voltage on the (K99) O2 1/1 Heater Control circuit for 2.0 seconds. Possible Causes INTERMITTENT DTC (K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE (K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO GROUND (K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN OR HIGH RESISTANCE (A15) FUSED ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE OXYGEN SENSOR ENGINE CONTROL MODULE (ECM) Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS Diagnostic Test 1. DTC IS ACTIVE Ignition on, engine not running. With the scan tool, Clear DTCs in the Engine Control Module (ECM). Start the engine and allow it to reach normal operating temperature. With the scan tool, select View DTCs.
Page 4 of 8 Is the status Active for this DTC? Go To 2 Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS 2. (K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE Turn the ignition off. Disconnect the Oxygen Sensor harness connector. Disconnect the Engine Control Module (ECM) harness connector. Remove the ASD Relay from the IPM. Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector. Turn the ignition on. Measure the voltage of the (K99) O2 1/1 Heater Control circuit in the Oxygen Sensor harness connector. Is there any voltage present? Repair the (K99) O2 1/1 Heater Control circuit for a short to voltage.
Page 5 of 8 Go to 3 3. (K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO GROUND Turn the ignition off. Remove the jumper wire and install the ASD Relay. Measure the resistance between ground and the (K99) O2 1/1 Heater Control circuit in the Oxygen Sensor harness connector. Is the resistance above 1000 ohms? Go to 4 Repair the (K99) O2 1/1 Heater Control circuit for a short to ground. 4. (K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN OR HIGH RESISTANCE Measure the resistance of the (K99) O2 1/1 Heater Control circuit between the Oxygen Sensor harness connector and the Engine Control Module (ECM) harness connector. Is the resistance below 10.0 ohms?
Page 6 of 8 Go to 5 Repair the (K99) O2 1/1 Heater Control circuit for an open circuit or high resistance. 5. (A15) FUSED ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE Turn the ignition on. Measure the resistance of the (A15) Fused ASD Relay Output circuit between the Oxygen Sensor harness connector and the ASD Relay connector. Is the resistance below 10.0 ohms? Go to 6 Repair the (A15) Fused ASD Relay Output circuit for an open circuit or high resistance. 6. OXYGEN SENSOR
Page 7 of 8 Turn the ignition off. Connect the Engine Control Module (ECM) harness connector. Replace the Oxygen Sensor in accordance with the Service Information. Turn the ignition on. With the scan tool, Clear DTCs. Start the engine and allow it to reach normal operating temperature. With the scan tool, select View DTCs. Is the status Active for this DTC? Go to 7 Test Complete. 7. ENGINE CONTROL MODULE (ECM) Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor and the Engine Control Module (ECM). Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Refer to any Technical Service Bulletins that may apply. Were any problems found? Repair as necessary.
Page 8 of 8 Replace the Engine Control Module (ECM) in accordance with the Service Information.