Radio switches on/off by itself

[MattL]

My RX450H has the same symptoms. Agree that it is worse at the start of a journey, and seems related to bumps in the road. 

A couple of years ago I took it to a car audio specialist. They removed the head unit and tested it, then told me it needed a new logic board, cost £1480+VAT.  I said I'd think about it, and asked them to reinstall the unit.  They charged about £100 for the diagnosis.  That removal and refit on its own fixed it and the problem went away completely for almost three years.  However, it has very recently started playing up again.

That it was temporarily fixed by the refitting makes me think that it's more likely to be a bad connector somewhere, possibly corrosion that was removed during the refitting and had since built up again...?  It just makes me think that a problem internal to either the head unit or the amp seems unlikely.

[MUDGUTS]

6 hours ago, MattL said:

My RX450H has the same symptoms. Agree that it is worse at the start of a journey, and seems related to bumps in the road. 

A couple of years ago I took it to a car audio specialist. They removed the head unit and tested it, then told me it needed a new logic board, cost £1480+VAT.  I said I'd think about it, and asked them to reinstall the unit.  They charged about £100 for the diagnosis.  That removal and refit on its own fixed it and the problem went away completely for almost three years.  However, it has very recently started playing up again.

That it was temporarily fixed by the refitting makes me think that it's more likely to be a bad connector somewhere, possibly corrosion that was removed during the refitting and had since built up again...?  It just makes me think that a problem internal to either the head unit or the amp seems unlikely.

I have had hours of fun with this issue on my car. When I get a chance I will be removing the trim and disconnecting then reconnecting, there’s nothing to lose. My theory is it’s a dry joint or something. I’ve tried pulling various fuses, etc. but as you say remaking those connections could clear a bit of corrosion. 
 

I’ll report back. 

[MattL]

Sounds good... suggest getting some contact cleaner spray.

I think I've noticed pressing up under the glove box seems to affect it, though I guess that could be lifting a big chunk of connected wiring.

[MUDGUTS]

Update: 

I removed the unit today, gave it a good vacuum, including the two little cooling fans. Using contact cleaner, I cleaned all the plugs and sockets, both on the unit and car.

Hopefully this will do the trick. It seems quite OK at the moment, only time will tell though. At least I’ve learned how to swap the unit, which is quite an easy process. The video below is the best guide I found. There are others, which show a whole lot more trim removal but that’s not necessary.

Removal of RX 450h Radio YouTube

If/when you drop the bolts, removing the panel below the shifter assembly will be where they drop out. Mine got stuck in the side panels, so a quick thump will release them.

A couple of observations:

I don’t think it’s necessary to switch the ignition to move the shifter knob, you could use the ‘Shift Lock’ button.

You could get a warning on the dash about SRS/Airbag system. I guess this is because I had removed the unit with ignition on? This disappeared once everything was back together and to be sure I used my fault code reader to check later and cleared a couple of historic faults, another was aerial disconnected or something. 

[MUDGUTS]

So far - so good. I’ve done a couple of 30-60 minute journeys including quite a lot of bumps in the road. Usually this would send the audio off its rocker. It’s been perfect.