LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 84 (Engine Control System Self-Diagnostics - 3.1L Engine) >> Diagnostic Tests >> DTC P0141: Ho2S Heater Performance (Bank 1; Sensor 2) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
  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.
    NOTE: If the engine has just been operating, allow engine to cool until near bias voltage is observed on scan tool before proceeding.
  2. Turn ignition on, with engine off. Monitor HO2S 2 voltage on the scan tool. Does the HO2S 2 voltage go to greater than or less than the previously stabilized voltage, by at least as much as 100 millivolts within 2 minutes? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
    NOTE: Ensure test light is connected to a good ground.
  4. Disconnect the HO2S 2 electrical connector. Turn ignition on, with engine off. Connect a test light between the HO2S 2 heater ignition voltage circuit, in the harness side of the HO2S connector, and ground. Does the test light illuminate? If yes, go to next step. If no, go to step  7.
  5. Turn ignition off. Connect a test light between the HO2S 2 heater ignition voltage circuit, in the harness side of the HO2S connector, and the HO2S 2 heater ground circuit. Turn ignition on, with engine off. Does the test light illuminate? If yes, go to next step. If no, go to step  10.
    NOTE: The heater element resistance will vary according to HO2S temperature. A hot HO2S heater element will have a higher resistance than at room temperature.
  6. Turn ignition off. Leave the HO2S connector disconnected. Allow the engine to cool for at least 15 minutes. Measure the HO2S 2 heater resistance at the HO2S 2 pigtail connector using a Digital Multimeter (DMM). Resistance should be within 2-20 ohms? If no, go to step  11.
  7. Test the HO2S 2 heater ignition voltage circuit for an open fuse. Did you find an open fuse? If yes, go to next step. If no, go to step  9.
  8. Locate and repair the short to ground in the HO2S 2 heater ignition voltage circuit and replace the fuse. After repairs, go to step  13.
  9. Repair the open or high resistance condition in the HO2S 2 heater ignition voltage circuit. After repairs, go to step  13.
  10. Repair the open or high resistance condition in the HO2S 2 heater ground circuit. After repairs, go to step  13.
  11. Before continuing, inspect for poor connections at the HO2S 2 connector. Did you find and correct the condition? If yes, go to step  13. If no, go to next step.
  12. Replace the HO2S 2. After repairs, go to next step.
  13. Use the scan tool in order to clear the DTCs. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  14. Using scan tool, observe stored information and 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.
scientia non olet · About LEMON Manuals