Anyone got any clues please? Headunit comes on when doors unlocked

[CJW]

Afternoon

T6 has just started this behaviour - headunit comes on upon fob door unlock.

It’s an aftermarket Sony connected via a CANBuS adapter from Jason at Absolut. It’s been working fine for at least a year. Used to be the case that HU would be off until first stage of key turn. Now it comes on when unlocking, and goes off with locking.

Bit of an issue soon because I’m not sure I can rely on the family to manually turn it off if they open the doors and have picnic etc. could easily result in a flat battery.

I have installed a DSP and sub recently, but they’re powered by the leisure battery and I’m using a remote signal from the back of the head unit, tapping into the red wire. I unplugged the remote wire to double check there wasn’t some back emf but the behaviour stays.

I’ve checked that continuous and switched power are OK and the right way round at the back of the HU.

I also noticed that the van locks itself if the key is not inserted after 30s, despite drivers door being opened and then shut, which may be connected. Door microswitch seems to be OK cos the door open warning on the dash responds as expected to the driver’s door being open / closed.

Have disconnected the battery for 20 mins, factory reset the HU, to no avail.

VCDS not much use since it needs ign to talk to the BCM.

Unlike the Kenwood, there are no settings to control this behaviour on the Sony.

Am a bit stumped. Only things that I can think of are:

• ECU reset through cap discharge
• Swap out the Canbus adapter

Any T6 hyper mind got any other ideas of things for me to try please?


Many thanks

 

[CJW]

…no faults on VCDS

 

[mmi]

VCDS not much use since it needs ign to talk to the BCM.

VCDS does talk to BCM without ignition, even without having key in the lock cylinder. Just plug in the cable and enter directly to the BCM.
VCDS > Select Control Module > 09-Cent. Elect.

However, locking the van shuts down all communication via OBD port in about 60 seconds - which still leaves plenty of time to checks things with the BCM.

For analysing door lock status behaviour perhaps something useful for comparison in here::

Anyone Know What This Fault Is And Whats Broken?

Thanks for any info.

www.t6forum.com

 

[CJW]

VCDS does talk to BCM without ignition, even without having key in the lock cylinder. Just plug in the cable and enter directly to the BCM.
VCDS > Select Control Module > 09-Cent. Elect.

However, locking the van shuts down all communication via OBD port in about 60 seconds - which still leaves plenty of time to checks things with the BCM.

For analysing door lock status behaviour perhaps something useful for comparison in here::

Anyone Know What This Fault Is And Whats Broken?

Thanks for any info.

www.t6forum.com

That’s a really useful piece of info, thanks @mmi. 60s is easily long enough.

I’ll do some VCDS snooping on what’s happening upon unlock.

 

[CJW]

I sat in the van looking at measurement blocks relating to doors, interior lights, T30 terminal, and everything seems to be OK.

I’m completely stumped but kindly @Absolut5 has said he’ll put his brain and experience to it.

 

[catfood12]

Well, exactly the same happened to me when I installed an Alpine Halo 11 and CAN Interface. It was nuts, unlock the doors, radio comes on.

Buried very deep in the CAN Interface settings was a parameter 'Pre-Ignition' and was set to 30 seconds. I set this to zero and the problem went away. It's not on Google anywhere, or any of the instructions. I would venture to suggest there is some similar parameter in Sony Canbus adapter.

 

[CJW]

Well, exactly the same happened to me when I installed an Alpine Halo 11 and CAN Interface. It was nuts, unlock the doors, radio comes on.

Buried very deep in the CAN Interface settings was a parameter 'Pre-Ignition' and was set to 30 seconds. I set this to zero and the problem went away. It's not on Google anywhere, or any of the instructions. I would venture to suggest there is some similar parameter in Sony Canbus adapter.

View attachment 226569

Hi. Thank you for that. I did read about this and mistakenly put it in the first post as a Kenwood thing but you’re right it’s Alpine.

Unlike the Kenwood, there are no settings to control this behaviour on the Sony.

Sadly there is no such setting on the Sony.

I’ve literally just come inside from tinkering with it. Happily, I have found the fault - the CanBus adapter. Swapped it for my older CanBus adapter and it works properly however it can’t stay like that as the older one doesn’t support MFSW.

Thank again for your help though. It really is appreciated.