GM Issued a TechLink Article
Several C8 Corvette owners are reporting that they’re getting check engine lights and reduced engine power messages from their 2020 Corvette. However, they’re experiencing no performance issues.
Corvette Blogger noted that three separate owners reached out regarding this issue. You can read those emails sent to the publication by clicking here.
It’s more than just those three emails, though. General Motors has now issued a GM TechLink article about this particular issue. The article went live on 10/28/2020. We have included this message below. Please read through it if you’re experiencing any issues.
October 28, 2020
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 above) 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.
You can also refer to refer to #PIP5757. If you would like to see the GM TechLink article on GM’s website, click here.