1999 Infiniti G20 OBO DIAGNOSTIC CODES

1999 INFINITI G20
152,670 MILES • 4 CYL • FWD • AUTOMATIC
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LETSMITH
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  • 1 POST
CODES PO138, PO139, PO140
FAILED INSPECTION
Nov 5, 2010 at 10:15 AM
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WRENCHTECH
  • ✓ASE Certified Mechanic
  • 20,761 POSTS
  • ASE Certified Mechanic
All those codes refer to issues with the O/2 sensor for bank 1, sensor 2. That would be the downstream sensor. These problems may be the result of another condition in the engine that damaged the sensor but you have to start out by replacing the sensor and then see if any new codes set. I would be surprised if they did.
Nov 5, 2010 at 10:33 AM
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