DTCs Set in the TCM

Some 2020 Corvettes may have an illuminated Check Engine MIL and a reduced engine power message on the instrument cluster with no noticeable performance issues. DTCs P1967 (Serial Data Message Safety Performance 1) and/or P1968 (Serial Data Message Safety Performance 2) may be set in the Transmission Control Module (TCM).

Follow the diagnostics for these DTCs in the appropriate Service Information. If there are other DTCs set in the TCM, diagnose those DTCs first.

If only DTCs P1967 or P1968 are set, do not request a TCM replacement (Fig. 21) per #PIP5703 (TCM Restriction). Perform the even and odd-related clean procedures in GDS2 and a transmission service fast learn. After completing these procedures, re-evaluate the condition.

These conditions are not a performance issue with the TCM or transmission assembly. A software update is currently being evaluated.


Fig. 21


For additional information, refer to #PIP5757.


– Thanks to Steve Schipansky

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