Blank MyLink screen after dead battery? Try this...

[Sir Les]

I realise this may have been covered previously, but the info is usually buried deep within the thread and not readily visible. I'm hoping my recent experience will benefit others, especially as our VFs are getting on a bit now.

After 9 years of faithful and uneventful service, my original ACDelco battery suddenly decided to give up the ghost. Whilst out and about I went to start the car (keyless push button start) and... nothing, just a horrible repeating clicking noise from the starter solenoid and a myriad of error messages on the dash -all characteristic of low voltage and a flat battery. Finally, 'Battery Saver Active' appeared on the DIC, and the MyLink screen went blank. I switched everything off and called the RAA's roadside assistance as I was not at home, it was late on a Sunday evening and everything was shut. After an hour's wait the RAA guy arrived, fitted a new battery (correctly using an alternative 12 volt power source whilst doing so), tested it, and went on his way. I drove home, noticing that everything seemed to be working apart from a blank MyLink screen, no audible turning indicator noise, no park assist beeps, and no reversing camera. The car drove fine, and HVAC operation was normal.

I left it overnight to see if it would fix itself, but no dice. So I tried disconnecting the negative battery lead for 10 minutes and bingo! On startup the screen came back to life (thank goodness), and to my astonishment the only setting the car had forgotten was the time. Radio stations, GPS settings, seat positions, temperature settings -- all were as before (and yes, I know some of these are read from the key fob). So, if your battery goes flat and the MyLink screen stays blank after charging the battery or replacing it, try disconnecting the negative lead for 10 minutes in the first instance. It might just save you a lot of time and trouble (and money!) footling around with the fuses or the MyLink unit itself.

 

[Skylarking]

… and yes, I know some of these are read from the key fob

I didn‘t think the key fob itself stores any vehicle specific settings other than maybe the VIN.

It’s a guess but it’s more likely that Mylink simply stores settings for different key identities using the key identity as a lookup pointer.

 

[stooge]

It’s a guess but it’s more likely that Mylink simply stores settings for different key identities using the key identity as a lookup pointer.

yes.

the keyfob does not store anything, it has an identifier code and the vehicle saves settings based on that code when per key settings are used.

for some reason the mylink can go into a state where it does not respond to the startup message from the can and it is not isolated to the vf, its a glitch in many of the gm vehicles including the last few holdens with the newer hmi systems like the zb, colorado, acadia etc and the only way to sort the issue out is to pull the battery lead.

 

[Skylarking]

the keyfob does not store anything, it has an identifier code and the vehicle saves settings based on that code when per key settings are used.

I understood that the key had a unique ID (which the vehicle uses to look up the user settings for that key ID).

But I also was under the impression that the VIN was programmed to the key and the key also stored the number of programmed keys within vehicle as well as the last time the vehicle was unlocked.

Maybe that’s not the case for the VF but it’s the direction things are going…. the business approach seems to be the more data the better (which is just going to make it harder and harder for owners to change batteries themselves, be they key or car batteries…)

Programming Key Fob Transmitters – TechLink

gm-techlink.com

 

[stooge]

I understood that the key had a unique ID (which the vehicle uses to look up the user settings for that key ID).

But I also was under the impression that the VIN was programmed to the key and the key also stored the number of programmed keys within vehicle as well as the last time the vehicle was unlocked.

Naa the key is not programmed with anything during the pair process.
They key is manufactured with a unique id like a serial number and the vehicle identifier and the vehicle uses that identifier to save different settings per key