Chevrolets May Have Missing Connector Seals

This bulletin applies to 2015-2019 Chevy Tahoe and Suburban, 2015-2018 Silverado, 2019 Silverado LD and Silverado 2500/3500, and 2015-2019 Colorado vehicles equipped with 4WD. An intermittent service 4 wheel drive message may be displayed in the instrument cluster.

Mike Mavrigian

Information courtesy of Mitchell 1

Dec. 28, 2020

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The cause may be wiring terminal issues resulting from a missing seal around the wires. When diagnosing intermittent transfer case control module DTCs related to signal or circuit integrity including C0321, C0392, C0396, C0398, C0306, C039E or C038D, inspect the related connectors and ensure that the seals are properly installed in the connectors. Missing seals allow moisture inside the connector and will cause repeated conditions and/or different intermittent conditions.

Some connectors are serviced as a connector. Some have terminal leads and some are available as a harness only. If there is corrosion in the connector and needs to be replaced, the mating side of the connector should also be replaced, whether it is another connector or an electrical component.

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.

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.