LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 1998 >> Forward Control P30, 6.5 F, Standard >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Engine Controls - Tests W/Codes - 5.7L) >> Diagnostic Trouble Codes >> DTC P0155 - Ho2S Heater Circuit Bank 2, Sensor 1 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Install scan tool. Turn ignition on, with engine off. Monitor HO2S voltage using scan tool. If HO2S voltage gradually decreases by .15 volt (150 mV), go to DIAGNOSTIC AIDS. If HO2S voltage does not gradually decrease by .15 volt (150 mV), go to next step.
  3. Check HO2S ignition feed circuit fuse. If fuse is open, go to step 12). If fuse is okay, go to next step.
  4. Turn ignition off. Disconnect HO2S connector. Using test light, probe HO2S connector terminal "D" (engine harness side) to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step 7).
  5. Connect test light between terminals "C" and "D" of HO2S connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 8).
  6. Allow HO2S to cool for about 10 minutes. Using DVOM, check resistance between HO2S ignition feed and heater ground circuit at HO2S pigtail. If resistance is 3-10 ohms, go to step 9). If resistance is not 3-10 ohms, go to step 11).
  7. Repair open in HO2S ignition feed circuit. After repairs, go to step 14).
  8. Repair open in HO2S heater ground circuit. After repairs, go to step 14).
  9. Repair for poor connection at HO2S harness terminals. Repair as necessary. After repairs, go to step 14). If connection is okay, go to next step.
  10. Turn ignition off. Disconnect VCM harness connector. Check resistance between HO2S signal and low circuits. If resistance is greater than 5 ohms, go to step 13). If resistance is not greater than 5 ohms, go to next step.
  11. Replace HO2S. After replacing sensor, go to step 14).
  12. Repair short to ground in battery feed circuit. Replace fuse. After repairs, go to step 14).
  13. Repair open or poor connection in HO2S signal circuit or low circuit. After repairs, go to next step.
  14. Allow engine to cool down for about 30 minutes. Turn ignition on, engine off. Using scan tool, select DTC, CLEAR INFO function. Monitor HO2S reading on scan tool. If displayed voltage gradually decreases by 150 mV, go to next step. If displayed voltage does not gradually decrease by 150 mV, repeat step 3).
  15. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test. If not additional DTCs are set, system is okay.
scientia non olet · About LEMON Manuals