U1123 Adaptive Cruise Control Databus error code (intermittent)

Hi All,

Past two months I have been having several error codes in my Kodiaq, one of which is U1123 Databus error from Adaptive Cruise Control. Would appreciate any help in troubleshooting.

My Car: Skoda Kodiaq 2019, 1.5 TSI DADA engine,  150 Hp, 50k km on odometer, front-wheel drive, DSG, 7-seater.

Issue description:

• Occasionally EPC light comes on and car goes into limp mode (with message that computer has reduced max throttle to 3000 rpms to prevent damage to the engine)
• This comes at the same time with several error codes popping up (I don't know if they are related / triggered by the same root cause, or completely separate). I am describing them each in a different thread potentially to troubleshoot each one separately. In summary, the error codes I get are P0011 (camshaft over-advance timing), U1123 (Databus error value received for Adaptive Cruise Control), B108715 (left vent temperature sensor). My guess is that EPC light comes due to the camshaft issue, but not sure.
• At the same time, I get the "Start/Stop system error" message on the car dashboard and neither start/stop nor ACC work
• Shutting down the engine and restarting the car removes the EPC light, and the car continues to drive normally (no limp mode), ACC works fine, start/stop works fine
• The issue appears at random intervals - sometimes could happen 2-3 times per day, sometimes once per week. Lately frequency has increased.
• Perhaps completely unrelated, but also occasionally my windshield wipers would "turn on" by themselves and do one sweep cycle only. Sometimes it would repeat once again in 20-30 seconds. This is while they are in fully OFF mode (not in auto mode). I've noticed this happen sometimes when I drive over a speed bump on the road (driving slowly still), sometimes just on flat surface. It happens roughly once per 3-5 weeks in an unpredictable matter. Perhaps completely unrelated, but I am thinking if there is some sort of electrical glitch, or short circuit that gets triggered somewhere, perhaps its causing both errors.

What I've done so far to troubleshoot it:

• Went to local Skoda dealer to diagnose, who indicated that unless I have an active EPC light at the time I come they might not be able to find anything (with me ending up to pay a lot of money for the hours spent on diagnostics). As I cannot replicate the problem myself to make the EPC light come on at the time I can come to the dealership, it makes it difficult to use their services.
• Tried to turn off ACC and drive without it for a while (to localize if EPC light is caused by it or not). EPC light still went on, when reading the codes, all 4 codes came back
• I've seen that a number of people had these problems, but none seem to indicate exact solution for it. There were suggestions that just unplugging the negative terminal of the battery for 2-3 minutes could help reset the electronics. Others indicated that ACC needs to be recalibrated by the dealer. Others indicated that ACC radar might be physically off (due to hitting a bump) and needs to be put back in place.
• I tried scanning the car with several different apps. With one I got the same U1123 issue appear twice (after clearing and driving for a few days, the same U1123 again reappeared twice). With another app, I see two different issues related to Active Cruise Control module (but one is a power window switch issue on the passenger door, which as far as I can tell has nothing to do with ACC). See both of the results below.

Specific Questions I would like to ask for your help with:

• Is it safe to disconnect negative terminal of the battery to reset the electronics of the car? I've read that in these newer cars this could cause all sort of systems to lose their settings and the car for sure will need to be recalibrated by the dealer. Others say that after driving a few min post disconnecting and reconnecting the battery, the car "relearns" all settings by itself. Which is true? Has anyone done it on a 2019 Kodiaq?
• If the radar needs to be mechanically adjusted / popped back into place - does anyone know how to take off the cover to get to the radar? This does not sound like a possible solution to me, but who knows...
• What does the power window switch issue reported by one of the apps have to do with ACC? Could this be an indicator that eletronics in general need a reset?
• Could my battery be going bad, causing all these strange issues? How can I test? Voltage seems to be at 14.9v with engine running and 12.5v at rest.
• Are the software versions up to date? Perhaps simply a software update is needed?
• Do you have any other advise wrt how I can troubleshoot the ACC databus problem?

Scan results with one app:

13 Adaptive Cruise Control
        System description: ACCCONTIMQB
        Software number: 2Q0907572Q
        Software version: 0342
        Hardware number: 2Q0907572B
        Hardware version: H03
        
        Faults:
                U112300 - Databus error value received
                Intermittent                
                
                U112300 - Databus error value received
                Intermittent

Scan results with another app:

0936
Raw code: 0003A8
ECU: 13. Active cruise control
Status: Test failed, Confirmed
Skoda: Power window switch on the front passenger door-E107; Window lifter switch, passenger side-E107
Status bits: 1
Priority: 4
Frequency: 11
Unlearning index: 227
Odometer: 50450 km
Date, time: 2023.02.17 12:00:06
============6==============
2068
Raw code: 000814
ECU: 13. Active cruise control
Status: Test failed, Confirmed
Skoda: Optical Data Bus - System Disabled; Optical data bus system switched off
Status bits: 1
Priority: 6
Frequency: 11
Unlearning index: 227
Odometer: 50450 km
Date, time: 2023.02.17 12:00:05