kev_coupe

You need to strip the loom gomg into the back of the brown plug.

remove the shielding and you'll see 2 purple and 2 brown wires. Loop them together and you'll get your audio back.

Obviously keep the plug in case you get the monitor repaired and can put it back to factory.

Update for anyone else who is having this issue on a late model (2014) Vellfire.

On review of the wiring diagram and pin outs, figured out the Mi / Mo wires related to the brown plug.  Stripped the 2 black wires and found 2 smaller Purple / Brown wires.

Looped them out purple to purple and brown to brown.  Audio restored 💥

Adding some additional images of the back of the plug in here which will hopefully help someone in identifying the correct pins to bridge.

I managed to get the wiring diagram from Toyota based on the VIN number (clip of the relevant page below).  This document relates to a 2014 model with 18 speaker system, rear monitor and panoramic roof.

I'm yet to attempt to bridge the pins.  Looks from the diagram that the Mi Mo wires relate to the brown plug and not the larger white one as I originally thought.

Will update once confirmed.

Removed the head unit today and took a photo of the connectors if it would assist? 

Part number is 86100-58104

Gents I'm having the same problem with my 2014 Vellfire.  Head unit powers up, but no audio and unable to control the volume either via the adjust knob or the steering wheel controls.  The rear screen is also not working.

I've removed the rear screen to attempt bridging the pins as above, but my connectors are totally different...

I have the 18 speaker theatre system.  Is there somewhere I could view the wiring diagram for the 2014 model so I can attempt to bridge the correct pins and hopefully restore the audio?

Thanks in advance for any help!