John McG

My 2016 Q3 S-Line developed an intermittent fault by shutting down occassionally. When it does I can hear the hard disc drive clicking inside. By pressing the radio button up to 10 times it starts up again. The unit also when shutting down keeps power on the unit as it heats up overnight and can discharge the battery. Initially I thought it was caused by a low battery but have replaced the car battery with a new one with no improvement. Due to the hard drive clicking I thought it was at fault so had it re-imaged to an SSD drive which stopped the clicking but it still after a few weeks the intermittent fault returned.

The next step was fitting a replacement MMI head unit which was coded by my local Audi dealer. This unit has ended up with exactly the same fault as the original MMI head unit hence eliminates them as being faulty.

Running a VCDS scan it comes up with;

56-Radio-Status:Cannot be reached 1100

5F-Information Electr-Status: Cannot be reached 1100

Both these errors show while unit is all working and if you try clearing error codes it says there are non to clear.

Both these errors show while unit is all shut down and if you try clearing error codes it says there is a communication error for both.

It appears then that I am loosing some sort of communication from a control unit tied into the ignition as the MMI units obviously have no faults and they are still receiving power.

My question then is what controls this signal? The ECU or something else. For example when opening drivers door a signal from somewhere shuts MMI down.

The Audi dealer is not much help and charge whether they can fix it or not. Has anyone had similar problems plus possible solutions.

drgertol

You have VCDS, so post the full auto-scan here following the guidance from Ross-Tech: https://forums.ross-tech.com/index.php?threads/101/

The MMI3G system has several modules connected by the optical MOST bus -- main unit J794, radio R, and external amplifier J525. If either radio or sound system module fails, the entire system will appear to fail. Isolating modules from the MOST bus with optical loop connectors is a common means of diagnosing this problem.

Regarding power to the main unit J794, Terminal 30 (starter battery) voltage is supplied to the main unit at the QuadLock connector; its power-on state is determined by either MMI control button actuations or wake-up messages on the CAN bus network (hence, why the MMI display turns off when a door is opened and the ignition is OFF). You'll find that the MMI is still "on" for a least 15 minutes or so, as determined by the GEM on-off timer settings:

--g

John McG

Thank you for the quick response. I am waiting for updated VCDS plug and software (was using older borrowed version before) to repeat the scan. I will post it in a day or two. Do I need to go back to the dealer for optical loop connector diagnosis as I find them less than helpful.

drgertol

Who re-imaged the MMI3G HDD ? Do you know that it is initialized properly by the QNX O/S that runs the MMI ? The system will operate without an internal mass storage device (HDD or SDD), but NAV and MEDIA functions will not initialize properly -- RADIO and TEL functions are not affected by an absent HDD (or SDD).

Re MOST bus diagnosis, you need a set of these: The "male" connector is used to isolate the MMI main unit (J794) from the MOST bus, while the "female" connector is used to bypass other modules (e.g., radio, amp) from the bus to allow the main unit to operate without them. --g

John McG

The HDD reimaged to the SSD fine and everything worked as expected but still had that intermittent shutting down fault. That is why I replaced the MMI3G head unit with another but unfortunately this unit also shuts down with no regular pattern.
It certainly appears to be a fault with some other component on the MORE bus. I have ordered two bypass fibre plugs so will look further to see what is causing the communication error.
How many components on the MORE bus and how do I locate them on a 2016 Q3 8UG model? I assume the amp is the component in the back left hand side as I see the fibre bus.
Thanks for all your help.

John McG

I have just googled the part number of what I thought was the amp. but have found it is the radio unit for the face lift Q3. Once I get the bypass plugs I can easily isolation this to see if it has the intermittent fault. Where do I find the amp. then and any other components on the MORE bus?

drgertol

What is the radio module part number ? Bose sound PR-9VK will have a separate Bose amp fitted behind the left rear trim panel. Non-Bose PR-9VD drive speakers from the radio module, part number depending on the production year and sales market. A VCDS auto-scan will tell you what is supposed to be fitted to the car (based on the CAN Gateway installation configuration).

BTW, you write that you replaced the "main unit", assume that to be in the instrument panel. (1) These aren't exactly inexpensive to replace and (2) replacement always requires a dealer service department to remove Component Protection from the (new) main unit, otherwize, entertainment sound (radio, media) is disrupted without warning. --g

John McG

The radio module is Harman Becker 4G0 035 053 J so I assume from that it is a non Bose version (manufacture date June 2016).
Yes I replaced the main unit and had it's component protection removed by our local Audi dealer. (Unit cost $400 NZ about $200 US and dealer cost $300 NZ about $150 US) Everything worked as as should once that was done.
I left the HDD in the replacement unit rather than swapping the old units SSD drive.
The odd thing is the replacement unit when it shuts down you can hear the HDD clicking just as it was in the original unit.

I will hopefully get the latest VCDS scan to you in a couple of days.
Your help is appreciated.

drgertol

ETKA tells us that 4G0035053J is for Bose (PR-9VK) applications -- 4G0035056J is fitted in PR-9VD configurations. So, you should have a Bose amp 8X0035223D fitted in the rear of your Q3; the VCDS auto-scan will confirm. --g

John McG

Hi again. While looking for the amplifier I noticed water on radio head casing and around that area on the boot floor. Upon removing the multi-plug I found corrosion on some of the connectors and pins!! I have done a clean up of contact surfaces and applied some conducting paste before re-attaching.
So far every thing is working fine so I did a VCDS scan with the old software and have attached the result. There are still some errors showing with the radio but I intend making a better job of cleaning up the terminals tomorrow.
Hopefully you can identify what the two faults mean so far.
My newer scan software should be with me soon so I will scan again then to see what result appears.