2009 onwards Harman Becker
Please follow this flowchart when troubleshooting … we hear everyday ‘ the amps still faulty ‘ – by garages / mechanics who really don’t know how to troubleshoot properly , this often results in time wasted sending the unit back for us to test .. also an unnecessary expense .
Due to the rising costs of shipping – we are now in a position where we WILL have to charge for shipping if we get a unit back and it proves to be functioning correctly ….. take the time and follow all the steps .
This issue is usually down to either no power to the unit , people sometimes remove the fuse to stop the battery draining – and forget to replace it . It my also be the case that another MMI module may also be damaged . This is common on A6/Q7 models where the tuner or navigation drive can also be water damaged – we can repair both if required.
To check other units are ok – read the ‘ Loop MMI system ‘ section.
To check there is power to the unit you will require a voltage tester and also a remote control ( any TV or Hifi remote )
Remove the main black power plug – look at the left of the connector face on and you will see two terminals which are larger than the rest – these are the 12v positive and earth terminals – we suggest when your using a tester probe that a small piece of wire is inserted first to avoid ‘opening up’ the internal spade connector.
Another way of testing power is to unplug the fibre optic in/out plug (two orange wires) and use a light source or ideally a remote control – with the unit powered up point the remote at the socket on the amp and press a button on the remote – you should see a red light flash back at you. If there’s no red light , it will most likely be due to no power getting to the amplifier.
Occasionally we also find that someone has take the fibre cables from the connector and replaced them incorrectly – details are on this page.
This can happens for three reasons only – either the balance has been adjusted to one side .. or most commonly we find that the unit has been replaced previously and hasn’t been coded – this triggers ‘component protection’ and will allow the unit to function from one channel only. The best way to test this is to diagnostically scan the car and check the ‘ amplifier module ‘ section – it will probably report ‘coding error’ . To rectify this you will need to use ODIS or VAS to ‘pair’ the unit back to the vehicle. VCDS or ROSSTECH is not able to remove component protection.
Occasionally ( around 5% of repairs ) a badly water damaged or processor damaged unit may have corrupt data after repair , or , have corrupt or lost data in the gateway module of the car . When the unit is originally operating there is also data ( not just audio ) being transmitted and received by the mmi system , any ongoing interruption to this data will cause the data stream to be inconsistent and potentially cause a ‘ miss match ‘ in the stored data between both the amp and the car – this will trigger a coding issue.
Due to it being encrypted data , the only solution is to recode the unit.
Also previous attempts at repair may also lead to VIN data being lost or corrupted.
If someone has tried to ‘ code ‘ another unit to the car – the previous coding details are erased – hence the original correct unit will then need ‘ paired ‘.
Another common issue which we come across is … customer takes the car to a garage – garage try to reset or ‘ reboot ‘ the amplifier using VCDS or hand held diagnostic equipment – very often they erase or corrupt the coding detail … unit comes to us for repair .. on return the MMI system now requires coding – this is ONLY because the garage has affected the coding .
To test if the amplifier is functioning on the drivers side , try the handsfree or the navigation voice assist – it’ll come from the drivers side of the vehicle.
An example VCDS Log is here –
Check for 12v between brown and
red/purple wires.
