Hello everyone,
I am new to the forum and this is my first post. Forgive me for any mistakes I make along the way.

I purchased my first Corvette, a 2021 C8 3LT with a salvage title. The car only has 7800 miles.
The car was salvaged from Florida due to flood damage.
I applied for and received a rebuilt Indiana title.
I have driven the car a little over 600 miles.
The interior was replaced along with the radio and several modules including the ECU.
I love the car and have had no issues except that each time the car is started I get "service tire monitor system" and the tire pressure warning light stays on.
The tire pressures will not display on the dash. (I knew about this when I purchased the car).
Everything else works as it should.
I had a local dealership service the car and do the 7500 mile transmission drain and flush and asked them to fix the tire pressure issue.
After some back and forth, I was informed that GM would not help them with the issue due to the car having a branded title.
I contacted GM and sure enough they politely told me that the Corvette Technical Service Center would not be able to assist the dealership in any way due to the branded title.
I have been told that the problem is a simple compatibility issue with the new ECU and could easily be fixed if GM chose to do so.
The sad thing is that I can monitor the tire pressure on my phone with the Chevrolet app. The tire pressure displays fine.
I know that the ECU has been cracked, but I'm not sure if that helps in any way or where to go from here.
Some say I will just have to live with it.
If that's true then so be it.
I have no intention of ever selling the car so the branded title is not an issue for me.

Any ideas?

Thank you and Merry Christmas!

 

Unless you can take it in and pay for an aftermarket tune (dyno tune) you are on your own. Branded titles void manufacturer’s warranty’s and they will run away from branded title cars.

 

I saw a TPMS relearn the other day but forget if it was for a C8. They said press two buttons together on the fob and then click trough each tire while letting a little air out as you do it so the ECU knows which tire is which. That may work?

 

I would find a GM tech who works for cash on the side and get it sorted that way.

 

You are correct that all warranty coverage is void on a salvage vehicle. I knew this going in.
I made it clear to both the dealership and GM that I was not asking for any warranty service and fully expecting to pay for the work being done.
I paid for the service and the transmission flush, but was still refused the help from GM.
This seems to be is a "simple" programming issue that would incur no liability to GM for fixing it. In fact it should be a bonus to them as it would alert the driver (me) of a dangerous low tire issue (yes, I know I'm reaching)
I'm pretty sure the dealership could not fix the issue without the help of TSC so I'm not sure that an independent tech would be able to fix the issue.
I would gladly pay for the service if anyone knows of someone I could contact.
Its not really a big deal, but it is such a nice car that I really hate not to be able to fix such a simple issue.

 

I'd try to find an independent shop that is fluent in late model Corvettes or a knowledgeable dealer tech. It is likely there is some water damage in the wiring connectors or electronics. Or it could be as simple as needing a scan tool to get the components talking again. There are likely troubleshooting steps in the service manual if one wants to take the time.

 

I assume you mean the ECM, or Engine Control Module was replaced? Who did that? It requires programming and set up when it is replaced. If that programming was successful, and it must have been since everything else is working fine, I am skeptical that the issue with TPMS is related to an ECM issue. From the service manual TPM "system uses the body control module (BCM), driver information center, instrument cluster, remote control door lock receiver, and a radio frequency transmitting pressure sensor in each tire assembly. Each sensor has an internal power supply."

If you are seeing pressures on the remote app, and they are actually correct, then it indicates that the sensors in the tire are working. Also, the receiver in the car must be working, and the data are able to be transferred over the car network where they can be reported to on star and sent to you app. On the other hand, if the those pressures are default or not correct, then that expands the possible causes to other components.

Here is some info about that"

"If power is disconnected from the BCM or if the vehicle battery is disconnected each tire pressure sensor ID is retained but all of the tire pressure
information is lost. Under these circumstances the BCM cannot assume that the tire pressures were maintained over an unknown period of time.
Cars equipped with the driver information center will display dashes and the scan tool will indicate a default tire pressure value of
220kP(32 PSI) for each tire. To reactivate the sensors, the vehicle must be driven above 40 km/h(25 MPH) for at least
2min. When the sensors are activated, the driver information center displays the current tire pressures. The EL-52545 tire pressure monitor
sensor and RF diagnostic tool may also be used to activate the sensors as well.
The BCM has the ability to detect malfunctions within the tire pressure monitor system. In the event a DTC is set, the tire pressure monitor
indicator icon on the instrument cluster will flash for approximately 1 min. and then remain illuminated for the remainder of the key cycle. After a
key cycle and the instrument cluster bulb check has been completed the indicator will again flash for 1 min. and then remain illuminated if the DTC
persists. Any malfunction detected will cause the driver information center to display a service tire monitor system type message."

So, are you seeing any more of these symptoms? Do you have a DTC set?

 

Thank you so much for your detailed reply.
I am relatively sure that the restoration work was preformed by Dino's Corvette Salvage in Picayune, MS.
All the receipts for the parts show them as the "ship to"..
As far as the modules that were replaced, I apologize for my error(s) in terminologies as I repeated what I thought I was told.
Here is the list that I have the receipts for. Most of the parts were purchased new from Banner Parts Center in New Orleans,

84930046 Amplifier Assembly, Rdo Spkr
85528809 F-Module ASM,COMN INTERFACE(W/M/TEL XCVR)ECCN=5A002
84928056 F-(S) BLO Block Assembly, Bat Distribution Eng Compt Fuse
13548775 (S) Module MODULE ASM-BODY CONTROL
85115274 F-Radio Assembly, Rcvr Eccn=5A992
13542886 (S) Module Assembly, Serial Data Gateway
13534122 Generator Assembly,
12696743 Starter Assembly, .
85004976 Recorder Assembly, Veh Perf Data
Additionally, the seats, console, and carpet were replaced.

Pretty sure my phone displays correctly. Currently it is reading (cold) three different pressures. 30 and 30 on the front (and suggesting that I add 1 PSI) and 31 and 32 on the rear (also suggesting I add 1 PSI).
Previously this summer the pressure on one tire was high and suggested that I reduce pressure.
You are correct, the DIC displays dashes for the pressures and indicates "service tire monitor system".
I picked up the car and drove it 500 miles home. The battery has been maintained and the issue persists.
I was told by the dealership that they were scanning code U2A91 in the IPC and BCM? (VIN/ mileage not calibrated to each module?)
Maybe this is what TSC had the issue with and not the tire pressure problem?
My Indiana title states that the mileage is not actual. That is a non-issue for me but maybe not for the car?
That is pretty much all I have.
I really do appreciate your help.

 

OK. In the Service Manual it says that is "U2A91 Displays and Gauges - DTC U2A91". There is a diagnostic procedure for the code. Basically it says "Perform all necessary programming and setup procedures for the control module: Control module that has set the DTC". And, if that does not fix it, it says "Replace the component: Control module that has set the DTC". I'm not clear on how they know which module set it.

Has the dealer already followed that procedure and it did not remove the code? (which may, or may not resolve our actual problem). My guess is it is either the Body Control Module (BCM), or the P16 P16 Instrument Panel Cluster Control Module. There are programming and setup procedures for both. Even if they were not replaced, it might (I am guessing here) be necessary to perform the set up procedures for them. What did the dealer attempt to do, before contacting GM to no avail?

 

I'm also guessing, but I gathered that the dealer couldn't or wouldn't address the issue without the help (or permission) from TSC.(I think GM refers to it as TAC Technical Assistance Center)
I contacted GM support through social media and they were responsive each time, but refused to help in any way.
After contacting GM directly, the Dealership Service Manager informed me that they would not preform ANY work on the car from that point on.
I assume I made them mad or GM stepped in and suggested they back away from the car. I'm not sure.
That is why I began this thread hoping to find some outside guidance.
I just can't wrap my head around the tire pressure being the only issue in the whole scheme of things.
The mileage is actual on the car, but because of it being a branded title it is marked as "mileage not actual" on the title.
Since the title already says mileage not actual, I don't know why it would matter to GM what the odometer registered.
I assume if the IPC and BCM were both replaced it would require GM to be involved in matching up the programming to prevent false odometer abuses.
As I mentioned before, it is a wonderful car and I just hate that something so small can't be resolved.
I am still hopeful that there is a solution to this.

 

Maybe contact the folks that replaced the components? I think they must have more or less successfully installed and programmed the modules on your parts list. I would have thought (again a guess) that if they were not programmed properly, nothing would work. There is stuff in the manual about back office registration, and insuring matching information across certain modules. Its in the radio section but says
"Back Office Registration
The Radio must be registered with the GM Back Office in order to receive downloaded information such as approved applications, module
software updates, weather and traffic information for current location. The vehicle must have a Cellular or WiFi connection to complete the initial
registration process. This process will verify the assembly plant factory feed data from the BCM, CGM and Radio serial numbers to the VIN and
if the security checks are met, then the user must complete the registration process by entering email and required personal information. The
registration status can be verified through the Radio â€oeSetting – About selection.
When any of these secured ECU’s are replaced, a new serial number will be recorded during the service calibration process and appended to
the vehicles history data for uninterrupted back office connection."

So, in the bold sentence, when it say "any of these secured ECUs are replaced", its referring to the ones mentioned above - BCM, CGM, and Radio. I am not sure what CGM is - it only appears once in this paragraph above. Elsewhere I see references to the Serial Gateway Module, and also one, and only one, reference to a Central Gateway Module. The version of the manual I have is a 2020, and its got a few inconsistencies in terminology. I think it was written by committee. Its really not clear to me that Programming and Set Up procedures always require comms with GM. But even so, I think its an automated process - speculating now - so that when the tech hooks up the equipment, the connection to GM will be via internet to server. Maybe if the car is salvaged, its info is deleted from the GM servers? But there are others on the forum that will know much more about this than I do.

 

I really appreciate all you efforts. I did contact Dino's to see if anything had changed. The seller was told (I'm assuming by Dino's) that it was a simple programming solution but GM refused to cooperate.
He was to the point that he was just going to put a piece of black tape over the warning light and ignore it. He spent a lot of money to make the car right so I don't believe he was trying to short cut things, but I remember thinking at the time "this can't be that hard" and that I would have a dealership fix the issue after I had the rebuilt title in hand.
Apparently he was right and i was wrong..
I have not yet gotten a response from Dino's but it is the Christmas holiday.
I could try another dealership and see what they say.
This area of Indiana doesn't see too many C8s.
I sourced the dealership that I used in Ohio because they were selling 35-40 C8s annually and I figured they knew what they were doing.
I agree with your assessment that the modules just need to be programmed to communicate properly. I really thought it would not be a difficult process.
Thank you so much for taking the time to try to help me with this.

 

I did find this when I searched the code being thrown (U2A91)
Note bold and italicized engineering note in the last paragraph.

Condition:
Some dealerships may comment that after a module is replaced and programmed,
the odometer may display zero miles or the incorrect mileage. This condition is also
accompanied with any of the following current DTC's: U1973, U197E, U197F, U2A90,
U2A91, U1978, and/or U197F.
Cause: This condition may be caused if the VIN or mileage fails to write to the odometer
Correction:
If you experience this condition, do NOT replace any further modules or swap any modules from a like vehicle as
this can make it more dicult to repair the condition.
If unnecessary module replacement or module swapping is found, the repairs may not be covered under
warranty.
To correct this condition:
- If a module was replaced, make sure all programming, setup, learns, etc. have been completed, per SI
procedures. There have been cases where the BCM was replaced and the BCM setup was never completed
which caused this concern.
- If the above items do not correct the concern, then engineering will need to be involved. Please create a case
with the Technical Assistance Center (TAC) and document the issue including: customer's original issue, any
part(s) replaced, programming error codes, current DTC's, what the odometer displays, this PI number and any
additional details. TAC will engage engineering to correct this concern.

I think that maybe the above is where the issue lies. Engineering may be refusing to help because of the branded title.