Hey everyone,

Im experiencing some electrical and communication issues with my 2017 Z06, and I could really use some help. Heres a rundown of the symptoms and error codes Ive been encountering:



The car has a delayed start when using the key fob. It sometimes takes up to 40 seconds for the car to start, and the dash displays the Service: Theft Deterrent System message with a car and lock icon.

The car sometimes wont detect the key fob unless it is placed inside the emergency key slot.

After the car turns off, it seems to take a while before the key fob is recognized again.

After running the car, the battery voltage has dropped to 12.25V or lower, even though the car has been running for a while.



Error Codes:

U0100: Lost Communication with ECM/PCM

U0140: Lost Communication with Body Control Module

P0700: Transmission Control System (MIL Request)

B3031: Manufacturer Defined

U0198: Lost Communication with Telematic Control Module A



Ive checked the fuses, and most of them seem fine. Ive also tested the battery, and it seems to be charging properly, though Im still seeing strange voltage fluctuations.



Im thinking this may be related to the BCM but I wanted to ask the experts here for some advice. Has anyone experienced similar issues, and if so, did replacing the BCM solve the problem? Or is there another cause I might be missing?

 

Moved to C7 Tech for assistance.

 

Test the easy items first.

Have the battery in the FOB replaced. FOB's are very sensitive to its battery voltage.

Have the car's battery tested. Most auto parts stores will do it for free.

Also let the auto parts store check DTC's. Another freebie.

Let us know the results.

 

As mentioned, these are very finicky with battery issues. I would start by replacing the battery if you are seeing anything suspect with it. Your weird voltage fluctuations are a red flag for sure. Also check the grounds.

 

I’d first get your battery checked out and if the battery is only charging at 12.25 volts low voltage like that can cause those communication codes…modules don’t like low voltage…I’d also check the charging system and if that testing is over your head find an auto electric shop in your area.

 

If the battery is truly low as measured with a DVM.

Then it just might be Fantasy Island syndrome.
Instead of 'The plane, the plane"
Its "The wire, the wire"

(The small black wire on the Negative post, they like to break off.)
Check it out.