Those two codes seem to be becoming popular. I also wonder for some of the guys that had the same codes they ended up changing out the transmission as a sure enough safe bet even though it was something mild.

 

Seat heater light for driver comes on for about 8 seconds and then off. Then, will not come on at all until next ignition cycle. Dealer got new heater element and while it turns on does not get hot. They have Chevy involved to figure this out. Has to do with a module or something. Car has been at dealer since last Tuesday. I am not too worried about it, since I know they will fix it. It just seems to be a mystery to all. Fortunately, I feel good about the dealer, Bryner, who is working on it!

 

Brake Boost Recall -- has anyone had this fixed on their C8 yet. GM states that parts are still not available. There were 676 C8's affected built between March 2 and June 26th.
I did check the NHTSA web site and GM has kits available for the Buick, Chevy Trail Blazer and Cadillac vehicles but nothing on the C8.

 

I agree with the need for this. Good info to have when/if these issues arise and you are discussing with your dealer to get things fixed up... Thanks for creating this. Expecting to take delivery of my 21 CONV/Z51/Mag Ride in June....if they keep the factory open!!

 

2021 newer issue?

 

Any other info on this? I am waiting on a valve body for mine. I would like to know if there is a TSB on this?

 

This is all that I could find...

 

Here is the entire repair procedure including DTC codes;

Multiple Transmission DTCs Set

February 26, 2021Some 2020-2021 Corvette models may have multiple DTCs set in the Transmission Control Module (TCM). The DTCs may be caused by an internal transmission solenoid or switch sticking due to debris in the DCT TR-9080 transmission (RPO M1L). (Fig. 20) Based on the DTCs that are set, GDS2 should be used to perform the appropriate solenoid cleaning procedure.



Fig. 20



The cleaning procedure should be performed three times. If required, perform the solenoid cleaning for each additional DTC that may have set and complete the solenoid cleaning three times. Once completed, it will be necessary to perform the Service Clean Procedure followed by the Transmission Service Fast Learn.

TIP: The cleaning procedure is targeted for mechanical and hydraulic conditions. If circuit diagnostics are required to determine the repair, valve/solenoid cleaning, Service Clean, and the Service Fast Learn will not address the issue.



Cleaning Procedures Based on DTCs Set

Use GDS2 to perform the following cleaning procedures for the DTCs set in the TCM.

If DTCs P194F, P1950, P0747, P0746, P0777, P0776, P2809, P2808, P2724, P2723, P1955, P0797, P0796, P2715, P2714, P2818, P2817, P08C5, P08C4, P27BA, P27B9, P27C2, P27C1, P27CA, P27C9, P27D2, P27D1, P282A, P2829, P1956, P1957, P1958, P1959, and/or P2735 are set:

• Perform the system cleaning procedure based on the DTC that set.
• Next, perform the Service Clean Procedure and then the Service Fast Learn.
• If DTCs return, replace the valve body as necessary.

If DTCs P18A8, P18A9, P2821, P2820, P187D and/or P187E are set:

• Perform the system cleaning clean procedure based on the DTC that set.
• Next, perform the Service Clean Procedure and then the Service Fast Learn.
• If DTCs return, transmission replacement may be necessary. Contact the GM Technical Assistance Center (TAC) for more information prior to ordering a transmission.

If DTCs P2855, P2853, P2856, P2854, P0869, P0868, P0867, C2A18 and/or C2A19 are set:

• Perform the system cleaning clean procedure based on the DTC that set.
• Next, perform the Service Clean Procedure and then the Service Fast Learn.
• If DTCs return, replace the valve body as necessary, except if DTC P0867 (Transmission Fluid Pressure Performance) is set. No system pressure is either a serious mechanical issue or extremely low fluid level.

If DTCs: P0844, P0841, P0849, P0846, P0874, P0871, P0879 and/or P0876 are set:

• Perform the system cleaning clean procedure based on the DTC that set.
• Next, perform the Service Clean Procedure and then Service Fast Learn.
• If no other pressure DTCs are present, proceed to circuit diagnostics.

If DTCs: P1946, P1947, P1948, P1949, P194A, P194B, P194C, P194D, P194E, P073F, P074A, P074B, P074C, P074D, P074E, P074F, P07D8 and/or P073E are set:

• Perform system cleaning cleaning IF accompanied with low/high system pressure codes; otherwise, perform the Service Fast Learn.
• Failure of the Service Fast Learn would indicate a mechanical hardware condition.

Service Procedures

After recording and clearing the DTCs, and with the transmission at operating temperature, use GDS2 to perform the Transmission Service Cleaning Procedures. (Fig. 21)



Fig. 21



Select the transmission cleaning services that correspond with the DTCs set. (Fig. 22) Not all cleaning procedures listed need to be performed.

For more details about each cleaning procedure, refer to SI document #5501008 – K71 Transmission Control Module: Scan Tool Information.



Fig. 22



Perform the DTC solenoid cleaning procedure three times for each DTC set. Once the cleaning procedure has been completed three times, select the Configurations/Reset Functions in order to perform the Transmission Service Fast Learn procedure as needed.

Be sure to test drive the vehicle after performing the cleaning procedures to verify that the DTCs do not reset. If the DTCs reset, replace the Control Valve Solenoid (or Main Control Valve, MCV).

For additional information, refer to Bulletin #21-NA- 033.



– Thanks to Dave Rainey



Updated March 1,2021

 

Screen would not take commands from finger touch. Home button worked fine. left side of screen not responding at all. Some displays worked correctly other didn't. Could swipe to different screens with no problem. Could however touch screen in phone display and make calls.
Other pages frozen and not working. Cause was my Iphone needed to be shut down and restarted. That was the actual problem and not the C8 screen itself. After resetting Iphone the screen came back to normal operation. Crazy! Just in case someone else else this issue.

 

Well wanted to take the C8 out from Winter sleep today, 4 months hooked to a battery abilical cord ! ..... well the Frunk will not open with any switches because the car thinks its already open !!!! drove to the dealer ( FAMILY ) at 26MPH because in Limp mode.... anyone else have the problem. Again Frunk closed ... but car thinks its open , all switches non-operative ... because she thinks already open LOL

 

This has happened to a few people. If you pull the manual release under the dash to open the frunk lid and close the frunk lid again it will clear the frunk open code.

 

Pull the manual cord under the driver's side floorboard & then shut the Frunk. Had the same issue & the dealership had to replace a bad selinoid. The part was overnighted & fixed next day.

 

Yep, solenoid failure ... one on the way ... apparently these have a tendency to short out when the car comes out of SLEEP Mode... these gremlins were very apparent in the cars development and well known electrical issues ... some have made it to Production LOL

 

Had a similar problem with mine right out of the box. Would buck starting out in first gear, switching from reverse to drive and other gear changes, then get better as more throttle was applied.. They contacted the GM engineers and they did a odd even clutch cleaning via sps, what ever that is, and reinstalled the fast learn program. Solved immediately! Like night and day difference. Been perfect through the 1500 miles since.

 

Outstanding sorry for the hassle.

 

2 words Price gouging. So bad now that i gave up on getting a c8 and bought a low miles c7.

 

Yes, there are problems with the C8. But this is par for the course with all new generations. And as an FYI, there are much fewer problems with the C8 than there were with the release of the C6 and C7. See stats below originally posted by Zymurgy in another thread:

Per the NHTSA:
The 2005 Corvette has 569 Manufacturer Communications, 6 Recalls, 4 Investigations and 513 Complaints
The 2014 Corvette has 1468 Manufacturer Communications, 5 Recalls, 0 Investigations and 44 Complaints
The 2020 Corvette has 199 Manufacturers Communications, 4 Recalls, 0 Investigations and 20 Complaints

 

Good to know, puts these issues in perspective

 

My C8 is in the shop waiting on a new trany.
Can any advise how long it took to have theirs replaced?

 

Good for you - no experience with a warranty tranny. Keep us posted.