CHAPTER 8

Diagnosing Engine Faults with Diagnostic Trouble Codes

Learning Objectives

• 8-01 Discuss diagnostic trouble codes and how they affect engine operation.
• 8-02 Identify OBD II. code types.
• 8-03 Use Freeze Frame data to aid in engine diagnostics.
• 8-04 Interpret diagnostic trouble codes.
• 8-05 Illustrate diagnostic steps and datastream analysis.

ASE Education Foundation Tasks

See Appendix A to view the 2017 ASE Education Foundation Automobile Accreditation Task List Correlation Guide.

You Are the Automotive Technician

A 2015 Lincoln MKZ comes into your bay. It has an intermittent check engine light which the customer is concerned about. You scan the vehicle and find a pending code of P0141, an oxygen sensor heater circuit code. What should you do first as the technician in charge of the vehicle?

1. Replace the oxygen sensor.
2. Go through the diagnostic flow chart.
3. Clear the code and see if it reappears.