Diesel Data: Automotive Repair

Federal Models

DIAGNOSTIC PROCEDURE





1. Are there any other codes besides 21 or 28 being output?
- If YES proceed to relevant Diagnostic Trouble Code chart.
- If NO replace Oxygen Sensor.

NOTE: If Diagnostic Trouble Code "21" is output inspect / replace front Oxygen Sensor. If Diagnostic Trouble Code "28" is output, inspect / replace rear Oxygen Sensor.