What should a technician do if the oxygen sensor wiring harness is extended?

• A. The technician should reject the vehicle until the oxygen sensor harness is repaired
• B. The technician should note it and proceed
• C. The technician should replace the harness and continue
• D. The technician should request a Referee

Answer: (D)

Extending the oxygen sensor wiring can change the sensor’s signal and heater operation, which can skew emissions readings and catalyst performance. Because modifications to the oxygen sensor circuit can affect test results, this needs official review to determine if the extension is acceptable under current rules and how testing should proceed. The correct action is to request a Referee, who will evaluate the modification and decide whether the vehicle can be tested as-is, needs restoration to stock configuration, or requires a specific test approach. Treating the situation without referee input risks an invalid test result or noncompliance.