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Home >> GMC >> 1996 >> Forward Control 4.3 Z, Automatic >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Tests W/Codes - P Series (Gasoline) >> Diagnostic Trouble Codes >> DTC P1134 - Ho2S Transition Time Ratio Bank 1, Sensor 1 >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Install scan tool. Check if any other DTCs are set. If any other DTCs are set, go to applicable DTC test. If no other DTCs are set, go to next step.
  3. Start engine and idle until normal operating temperature is reached. Observe engine coolant temperature using scan tool while operating engine at a steady speed of 1200-2000 RPM for 2 minutes. After 2 minutes, if HO2S bank 1, sensor 1 voltage rapidly swings greater than and less than .3-.6 volt, go to next step. After 2 minutes, if HO2S bank 1, sensor 1 voltage does not rapidly swing greater than and less than .3-.6 volt, go to step 5).
  4. Observe scan tool with engine running at 1200-2000 RPM. If scan tool indicates closed loop operation, see DIAGNOSTIC AIDS. If scan tool does not indicate closed loop operation, go to step 8).
  5. Check if HO2S bank 1, sensor 1 voltage remains within .3-.6 volt longer than it swings outside of .3-.6 volt. If voltage remains within specification longer, go to step 10). If voltage does not remain within specification longer, go to next step.
  6. Check for poor connection at VCM. If a problem was found, go to step 10). If a problem was not found, go to next step.
  7. Check for poor connection at HO2S bank 1, sensor 1. If a problem was found, go to step 10). If a problem was not found, go to next step.
  8. Replace HO2S bank 1, sensor 1. Go to step 10).
  9. Check leaded fuel, incorrect gasket sealer and over rich operation as possible causes of HO2S contamination. If a problem was found, go to next step. If a problem was not found, go to step 11).
  10. Repair or replace as necessary. Go to next step.
  11. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P1134. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2).
  12. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
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