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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, 4WD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 2.0L >> Diagnostic Tests >> DTC P0140: Ho2S Circuit - Insufficient Activity (Sensor 2) >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Are any HO2S DTCs set other than DTC P0137, P0138 and P0140? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Start engine. Run the engine until the engine reaches a normal operating temperature. Increase the engine speed to 2000 RPM for one minute. Monitor the applicable HO2S voltage with a scan tool. Does the HO2S voltage switch below and above the specified range of 300-600 mV? If yes, go to next step. If no, go to step  5.
  4. Turn ignition on, with engine off. Perform the scan tool clear DTC information function. Operate the vehicle within Freeze Frame conditions as specified or until the applicable DTC diagnostic test has run. Does the HO2S voltage switch below and above the specified range of 300-600 mV? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  5. Turn ignition off. Disconnect the electrical connector of the suspect HO2S. Disconnect the C2 electrical connector of the PCM. Turn ignition on, with engine off. Connect a DVOM from ground to the oxygen sensor signal circuit on the harness side of the electrical connector. Is the voltage at zero volts? If yes, go to next step. If no, go to step  10.
  6. Turn ignition off. Connect the PCM C2 electrical connector. Turn ignition on, with engine off. Probe the HO2S ground circuit at the HO2S connector with a test light connected to battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step  8.
  7. Use the DVOM and select the Millivolt DC scale. Connect one lead of the DVOM to battery voltage. Connect the other lead of the DVOM to the signal circuit of the suspect HO2S. Start engine. Observe the HO2S voltage parameter on the scan tool. Is the voltage at 1000 mV? If yes, go to step  11. If no, go to step  9.
  8. Check for an open in the ground circuit of the HO2S. Repair as necessary. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  9. Check the HO2S signal circuit for open circuit, short to ground or high circuit resistance. Repair as necessary. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  10. Repair the short to voltage in the HO2S signal circuit. After repairs, go to step  13.
  11. Replace faulty HO2S. After repairs, go to step  13.
  12. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  13. Turn ignition off. Remove DOME fuse for 30 seconds (located in passenger compartment fuse block). Reinstall DOME fuse. Reset radio clock time. Start engine. Operate vehicle within the Conditions for Running the DTC or until DTC P0140 diagnostic test has run. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  14. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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