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Home >> Cadillac >> 1996 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1154 - Ho2S Transition Time Ratio Bank 2, Sensor 1 (Front) >> 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. Using scan tool, check if other DTC(s) are present. If other DTC(s) are present, diagnose affected DTC(s) first. If no other DTC(s) are present, go to next step.
  3. Start engine. Using scan tool, select ENGINE 1 and observe ECT display. Operate engine until temperature reaches 185°F (85°C). Note ENGINE SPEED and BNK 2 SEN 1 display. Operate engine at 1200-2000 RPM for about 2 minutes. After 2 minutes, check if front oxygen sensor voltage rapidly swings from less than .3 volt to greater than .6 volt. If oxygen sensor voltage is swinging as specified, go to next step. If oxygen sensor voltage is not swinging as specified, go to step 5).
  4. With engine at 1200-2000 RPM, note scan tool LOOP STATUS display. If scan tool display reads CLOSED, fault is not present. See DIAGNOSTIC AIDS. If scan tool display does not read CLOSED, go to step 8).
  5. If front oxygen sensor voltage remains between .3-.6 volt longer that it swings out of this range, go to step 8). If oxygen sensor voltage swings, go to next step.
  6. Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contact is okay, go to next step.
  7. Check terminal contact at front oxygen sensor connector. Repair as necessary. If harness connector is okay, go to next step.
  8. Replace front oxygen sensor. Check for possible sensor contamination, i.e. leaded fuel, incorrect gasket seal or over rich operation. If failure is caused by an over rich condition, check fuel injection system. See BASIC TESTING article.
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