Diagnose emissions and drivability concerns caused by the exhaust gas recirculation (EGR) system; inspect, test, service, and/or replace components of electrical/electronic sensors, controls, wiring, tubing, exhaust passages, vacuum/pressure controls, filters, and hoses of EGR system; determine the necessary action.

Diagnosis should include

using a five-gas analyzer
using a scan tool
interpreting emissions testing results
troubleshooting charts
comparing test results to service materials and manufacturer guidelines.

Components should include electrical/electronic sensors, controls, wiring, tubing, exhaust passages, vacuum/pressure controls, filters, and hoses of the EGR system.

Process/Skill Questions:

What might the typical customer complaint be for a stuck-open EGR valve?
What might be the consequences of having a plugged EGR system?
What is the function/operation of the EGR system?