Suspected MOST bus issue

benmays99 · 09-20-2021, 06:27 AM

Hi guys,
I'm having trouble figuring out the cause of the weird behaviour in my '09 E91 335i with CIC iDrive.
Every time I start the car the iDrive screen takes about 20 minutes to turn on and also the radio and parking sensors don't work for 20 minutes as well which makes me suspect there's a problem on the MOST ring?
I also get the SOS error on the dash so I tried a MOST bypass connector thing on the TCU unit under the boot floor but I still get the same symptoms.
Any ideas on what's causing this?
Thanks

ryan stewart · 09-20-2021, 06:36 AM

Go from device to device in the car when its not working and see if one of the input lights is either out or solid (not flashing slowly).

In my case the sat radio module crapped out, it was only outputting a solid light when the circuit was on while everything else would do a slow flashing when disconnected. Removing it and bypassing it resolved my issue.

09-20-2021, 06:27 AM	#1
benmays99 Registered 0 Rep 1 Posts Drives: '09 E91 335i N54 LCI Join Date: Sep 2021 Location: Kent, UK iTrader: (0)	Suspected MOST bus issue Hi guys, I'm having trouble figuring out the cause of the weird behaviour in my '09 E91 335i with CIC iDrive. Every time I start the car the iDrive screen takes about 20 minutes to turn on and also the radio and parking sensors don't work for 20 minutes as well which makes me suspect there's a problem on the MOST ring? I also get the SOS error on the dash so I tried a MOST bypass connector thing on the TCU unit under the boot floor but I still get the same symptoms. Any ideas on what's causing this? Thanks
	Appreciate 0 Tweet Quote

09-20-2021, 06:36 AM	#2
ryan stewart Major 2197 Rep 1,322 Posts Drives: 2008 328it Join Date: Aug 2012 Location: Atlanta, GA iTrader: (0)	Go from device to device in the car when its not working and see if one of the input lights is either out or solid (not flashing slowly). In my case the sat radio module crapped out, it was only outputting a solid light when the circuit was on while everything else would do a slow flashing when disconnected. Removing it and bypassing it resolved my issue.
	Appreciate 0 Quote