Service Repair

Chevy Corvettes are Running Rich

Sept. 14, 2020

This bulletin applies to 2016-2019 Chevy Corvette vehicles equipped with a 6.2L LT1, LT4 or LT5 engine. The vehicle may have a concern with the SES lamp on and a rich running condition.

Information courtesy of Mitchell 1

Mike Mavrigian

This bulletin applies to 2016-2019 Chevy Corvette vehicles equipped with a 6.2L LT1, LT4 or LT5 engine. The vehicle may have a concern with the SES lamp on and a rich running condition.

DTCs P0172 and P0175 may be stored. If normal diagnostics does not isolate the cause of the rich condition, disconnect the dirty side of the PCV system.

Plug the vacuum supply. Start the engine and monitor the fuel trim in closed loop. If the fuel trims return to normal, this is a good indicator that the high pressure fuel pump is leaking. With this concern, you will not see a lot of fuel in the crankcase, so changing the engine oil may not isolate the concern.

When the high pressure fuel pump leaks, the PCV will pull the fuel mist straight into the intake, causing the concern.

About the Author

Information courtesy of Mitchell 1

Information for Technical Service Bulletins comes from ProDemand, Mitchell 1's auto repair information software for domestic and import vehicles. Headquartered in San Diego, Mitchell 1 has provided quality repair information solutions to the automotive industry since 1918.

About the Author

Mike Mavrigian | Motor Age Editor

Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety of specialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.