Hey!

I've had some issues with my head unit/stereo.

I had water ingress which destroyed my old amp (a XQK500104) and i replaced it with a new one bearing a slightly different part number (XQK500105).

After this i finally (at least 70% of the time) can get past the Land Rover screen (no blinking power led - it stays solid).

But now i cant select CD or TV. The buttons look normal, but nothing happens when i press it. Furthermore, the volume knob on the IHU does not do anything, but the steering wheel buttons work.

I've tried to bypass both the bluetooth and tv module, but to no avail.

Scanned with GAP IID and i get the following codes:

U2003-31 (28 ) Fibre optic communication bus - Frequency modulation/pulse width modulation failure - no signal (This one comes and goes)
U1A03-62 (2B) Vehicle configuration parameter - Algorithm based failure - signal compare failure

Click image to enlarge

Update - Solved

Finally I managed to solve this issue!

It seems that switching the AMP with a newer unit made the ACM ECU not recognize the amp.

What I did was:

1. Hold the info button (to make the IHU create a popup) - I could not do the following steps until i first did this. (I tried about 25 times for over 4 days, hard reset etc.)
2. Hold the top of the screen for 5 seconds (at the main menu)
3. Hold the NAV button for 5 seconds immediately after
4. Enter the code 134679
5. Run the MOST Test until it stops or reaches 1500 ish
6. Hit the Reset MOST NetServices button
7. Hit the ID button and wait until it stops
8. Exit the menu and voila! It's all back.

Wow. Thank you for this. I've had similar problems and your instructions to reset the MOSTServices and then hit the ID button did the trick. I don't know how you figured this out but I am VERY grateful as I've been through allllll the various other suggestions on the internet and to no avail!

For future reference to others who may benefit from this solution here were my symptoms, which were slightly different than the OP's.

First, we start with the standard BT module conking out: one day my touchscreen wouldn't power past the LR logo and the power button light would blink constantly. I added a fiber optic loop to the BT module and unplugged the wiring harness. This sort of returned the touchscreen functionality...maybe a quarter of the time the LR logo would stay up but I could get into the normal menus with the 'touch screen for 5s, then press SatNav button for 5s' trick. During all of this, my radio worked, sorta. I could change the volume only with the steering wheel rocker and change stations only with the physical button. The Radio page would never show the station data nor would the presets show any values. There was ONE time when the preset buttons actually worked to changed the station but even then there was no station ID.
Also during this time:

The Fuel Mileage page would have no values
The Offroad page would have no values, the suspension graphic did not work, and the wheels did not turn with the steering wheel.
Sat Radio button sometimes appeared and sometimes did not.
Sat Radio, CD, DVD, and Aux soft buttons registered presses but nothing happened.
Date would reset every time the car was turned off
Time would loose several minutes a day (Despite new AGM H8 battery)
SatNav seemed to always work, though!!