be performed.1. Add TerraDiesel ™ Fuel Injector Cleaner (201255) to the vehicle’s fuel tank.2. Remove the plastic engine cover.3. If engine is hot, the EGR cooler must be cooled – see note in step 8. GM Duramax 6.6 Liter (LML) 2011- 2016 Diesel EGR System ZIT18-03165 ...