Head unit issue

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richg

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The head unit in our 2012 LR4 has suddenly become inoperable. You cannot select an audio source for the stereo, it will not pair to a phone, it will not play any audio, navigation does not load, and when you reverse, the backup camera brings up a black screen instead. The head unit resets itself randomly, but is still non-functioning.

Has anyone else experienced this issue? It started out of nowhere.

rich
 

ryanjl

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I had something similar, though not identical, 3 or 4 months ago. I disconnected the battery for a few minutes, then reconnected it. It force-reset everything and it has worked fine since.

Not sure it will fix your issue, but maybe worth a shot.
 

richg

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Unfortunately the battery disconnect did not work.

These are the items which are non-functional:

All stereo functions (several of the options are "greyed" out so they can't even be selected).
Backup camera
bluetooth connectivity
navigation

I can still:
Go into 4x4 settings
Adjust some basic settings (such as clock, etc)

Has anyone else had this issue?
 
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jaguardoc504

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Mine does this like every 4-5 months. I just restart the vehicle, and all is good.
Complete shut down, lock the doors, wait a few minutes, then unlock (to wake up), and everything should be OK.

Also you may have a bad amp/processor.
 

richg

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Unfortunately, multiple attempts at restarts and battery disconnects have not fixed the problem. Based upon the multiple systems that are non functional, I believe it is something on the MOST ring network that has gone bad. Having a bit of difficulty finding a complete diagram showing everything on the MOST ring for my 2012 truck. The workshop manual I have seems to break it out by individual section.
 
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richg

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So it appears the amp is not sending along the MOST signal. I have red light going into the amp, but don't have anything at the sat radio module. I installed one of these: https://www.amazon.com/gp/product/B01M5IYTD9/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 to bypass around the amp, and get red light at the sat radio module now.

With the bypass installed, I can get the backup camera to function, but everything else is still dead. Navigation doesn't work, bluetooth doesn't work, cannot select any audio source. Wondering if I have two problems, the amp and the main integrated audio module. All audio related fuses are OK, and supply voltage is present at the amp (~14.6V which is higher than I'm used to on my other cars, but not sure that its abnormal for these trucks).

rich
 

umbertob

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Based on your troubleshooting results, my guess would be that you have a bad amp. The integrated audio module processes the one device in the loop that doesn't require audio amplification (the camera) but disables every other source, since the power amplifier is now bypassed.
 

richg

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Thanks for the reply. I guess I can see how the IAM would simply disable all of the rest if the amp is non functional. I'm hopeful that is all it is.

So I've found a bunch of used amps on car-part.com (mostly out of other rover vehicles, but I'm guessing they are the same part as my "high line" amp), but will I need the dealer to program the truck to accept them? And what about a software update?

For reference, my amp looks to be PN BJ32-19C164-AF.
 
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Kris JM

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Hi there, we're almost 3 years later but I'm curious what happened here? I just had the exact same issue, and in Richmond, BC, they want $700 to tell me what part needs to be replaced, and then $2500-$4500 for either head unit (hard drive) or amplifier replacement.

Thanks!
 

richg

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As this came up again recently on another thread, realized I never closed out the original one. My issue was the factory amp "turn-on" wire went bad somehow. Below are some troubleshooting details and how I fixed it.

The amp is on the passenger side in the cargo area.

There are two fused +12V supplies to the amp.

Central Junction Box, F41, 5A, a yellow & red wire to the amp
Engine Junction Box, F69, 40A, a fat red wire to the amp

These feeds are on different plugs at the amp, the main power feed is the fat red wire, the "turn on" is the smaller yellow & red wire.

With the truck on, you should see 12-14V at the connector for each of these wires. On my truck, I was only measuring .7V on the yellow/red wire (so the amp would not turn on). So somewhere between the central junction box and the amp, something went bad.

My fix was to make a jumper from the 12V signal on the sat radio over to the yellow/red wire at the amp connector (cut the yellow/red wire, isolate the end that heads back to the CJB so you don't risk causing a future short, then connect your jumper to the end still attached to the connector). With it like this, the amp turn-on is now running off the sat radio fuse, but I haven't had an issue for the 5 years I've been running like this.

Rich
 

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