iPhone is continually lowered when connect to GMC

[krb49]

Didn’t work for me either iPhone XR.  

[Kevinsgmc2020]

Same issue. Thought it was me. 90k on a Sierra 3500 dually and can’t tell when my phones ringing!! Very aggravating!!

[eppieguy]

On 7/23/2020 at 8:23 AM, MCM3M said:

Hmm, worked for me. Is your problem with an iPhone?

Yes, Pro 11 on 13.6

[RSmock]

https://static.nhtsa.gov/odi/tsbs/2019/MC-10169351-9999.pdf

 

This is the fix for the volume issue on GM vehicles with iPhone. 

[Gatorz62]

2020 Sierra 2500 Denali.  Same issue and the "fix" (sounds and haptics) does not work.  I Phone XR with latest update as of today.  Also, updated latest software for the truck.   Frustrating.  For now I have just disconnected my BT from the vehicle.  

 

I have also had issues with radio muting itself with no fix until the engine is turned off for a couple minutes.   

[22’s]

Got something for people to try. Go into settings, go to Siri, go to announce messages, and turn that off. This worked for me. 

[SPASierra]

Checked both of my phones, and neither one have "Change with Buttons" turned on.  Just got the truck a week ago, and this has already become annoying.  Will check the version on my Infotainment as well.

[cordelearts]

Simple fix, the sound is controlled manually by the volume steering wheel. Sometimes the volume is behind the steering wheel like you are holding it.

[Big Mick]

 

I found this and I am going to try it.
 

Why does my iPhone volume keep going down?

Attention Aware, Reduce Loud Sounds, and accidental button presses can all cause your iPhone's volume to decrease automatically. To fix this issue, you can disable Attention-Aware features, turn off the ability to change volume with buttons, and disable Reduce Loud Sounds.