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Home › Saturn › 2000 › LS2 Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0130: Ho2S Circuit - Bank 1, Sensor 1 › Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Start engine. Using scan tool, monitor loop status (bank 1). If loop status is open, go to next step. If loop status is closed, problem is intermittent. See DIAGNOSTIC AIDS .
  3. Turn ignition off. Disconnect ECM harness connector J1. Disconnect HO2S bank 1, sensor 1 harness connector. Check for continuity between HO2S harness connector terminal No. 2 (Purple wire) and terminals No. 3 (Tan wire), No. 1 (Purple/White wire) and No. 6 (Tan wire). Check for continuity between terminal No. 3 (Tan wire) and terminals No. 1 (Purple/White wire) and No. 6 (Tan wire). Check for continuity between terminals No. 1 (Purple/White wire) and No. 6 (Tan wire). If continuity exists in any of the circuits, repair short in affected circuit(s). If continuity does not exist in any of the circuits, go to next step.
  4. Reconnect ECM harness connector J1. Turn ignition on, with engine off. Using DVOM, check voltage on HO2S harness connector terminal No. 2 (Purple wire), then on terminal No. 3 (Tan wire). If 2-4 volts are present on both circuits, go to next step. If less than 2 volts are present in one of the circuits, go to step  7. If greater than 4 volts are present in one of the circuits, repair short to voltage in affected circuit.
  5. Measure voltage on HO2S harness connector terminal No. 1 (Purple/White wire), then on terminal No. 6 (Tan wire). If 0.2-0.4 volt is present on both circuits, replace HO2S bank 1, sensor 1. If greater than 0.4 volt is present, repair short to voltage in circuit. If less than 0.2 volt is present, go to next step.
  6. Measure voltage between battery positive terminal and affected circuit (with less than 0.2 volt). If battery voltage is present, repair grounded circuit. If battery voltage is not present, check for open in circuit. Repair as necessary. If circuit is okay, check for terminal tightness at connectors. Repair as necessary. If connectors are okay, replace ECM.
  7. Measure voltage between battery positive terminal and affected circuit (does not have 2-4 volts). If battery voltage is present, repair grounded circuit. If battery voltage is not present, check for open in circuit. Repair as necessary. If circuit is okay, check for terminal tightness at connectors. Repair as necessary. If connectors are okay, replace ECM.
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