EPC error light

[plainmad]

Hello all,

I hope you can help me with an issue with my golf that i'm having.

Its a mk7.5 golf gti which i've had for nearly 4 year now.
I noticed that last year that the stop start wasn't kicking in as often and very occasionally it would throw up an epc & stop start and acc assist error. It went in for a service and they said the battery failed the test they do.
I carried on driving for another month and the epc error etc got more frequent especially when left unused for a couple of days so i installed a new battery and coded it to the car. This seemed to solved the issues and i thought that was it.

However recently the epc errors are getting worse. These errors seem to come up when the car has not been used and whilst at first it seemed to be if it had been a week they are now doing it every night almost and today i drove it to work this morning and then this afternoon on the way home it showed it.
The error goes away if i drive only for a few mins and restart the car and the stop start works as soon as the error has gone. This with a new battery makes me think it isn't the battery voltage being low.
The symptons when the car has this is it shows EPC light, stop start error and it also says acc unavailable. When clicking on the car menu on the infotainment system it just shows stop start error. Also the car is sluggish (compared to normal) and seems to go into limp home mode.

Today when i got home i plugged in OBDEleven and gave it a full scan which come up with these errors.

13 Adaptive Cruise Control

    System description: ACC BOSCH MQB
    Software number: 5Q0907572J
    Software version: 0654
    Hardware number: 3QF907572
    Hardware version: H10
    ODX name: EV_ACCBOSCHVW416
    ODX version: 002006
    Long coding: 2B00608159FFC728949C810560400600000000000000000000

    Trouble codes:
        U112300 - Databus error value received
            Intermittent


01 Engine

    System description: 2.0l R4 TFSI
    Software number: 5G0906259C
    Software version: 0002
    Hardware number: 06K907425B
    Hardware version: H13
    ODX name: EV_ECM20TFS0205G0906259C
    ODX version: 001005
    Long coding: 091900122444050B2000

    Trouble codes:
        P023400 - Turbo/Super Charger Overboost Condition
            Intermittent
        U112300 - Databus error value received
            Intermittent
        U021200 - Lost Communication With Steering Column Control Module
            Intermittent
        P00AF00 - Turbocharger/Supercharger Boost Control "A" Module Performance
            Intermittent


D7 LED Module Right

    System description: LED1R
    Software number: 7P5941572A
    Software version: 0002
    Hardware number: 7P5941572A
    Hardware version: H06
    ODX name: EV_LEDMinMaxR_KEBODAVW481
    ODX version: 001003

    Trouble codes:
        C119AF6 - Static AFS light Overtemperature protection active
            Intermittent

The light control module also have a supply voltage to low but i understand this this is quite normal.

I've cleared the codes for now and will try to scan next time the error comes on but has anyone got any ideas on what it might be in the meantime.

The only modifications i've done to the car is to install a dash cam hard-wired in and the intermittent fault was here before that so i don't think is linked

Thanks all in advance

[Watts]

Check the battery. My guess is that it will be low voltage and that something, likely the dashcam, is slowly draining it. If it is low, disconnect the dashcam and get the battery charged up and see how you go. Don't dismiss battery drain until you've checked as you do say the problem is worse when the car hasn't been used for a while and a low voltage battery will cause all sorts of errors including making the car go into limp mode. After that you need to get it booked in and looked at. Good luck.

[plainmad]

Even though I put a new battery in?

And the dash cam is wired in off a switched fuse so turns off when the electrics go off

[Watts]

I would always check the obvious first, don't discount it until you're sure.

[birdherder]

Resurrecting this thread in the hopes that OP is still getting notifications.  @Plainmad, did you ever resolve this issue?  I am in a 2018 NAR Golf R (6MT) with very similar issues to yours!  Error codes are similar.  Getting the EPC light coming on in conjunction with the ACC warning.  Pattern exactly the same as yours. Started years ago after being parked for long periods, resolves with restart, now becoming more frequent.  Boost is reduced when the light is on.  Everything normal after restart.  I changed the battery for similar reasons, also have a hardwired dashcam which powers down when the car shuts off.  Battery change fixed some low voltage errors I was getting before, but not this issue!  I am desperately trying to find information on this pattern, and found your post.  How did it end up for you?

EPC Error codes below for those curious.  Manual Rs have no Stop/Start system in NAR.

01 Engine

    System description: 2.0l R4 TFSI
    Software number: 8V0906259P
    Software version: 0001
    Hardware number: 06K907425E
    Hardware version: H13
    ODX name: EV_ECM20TFS0208V0906259P
    ODX version: 001003
    Long coding: 091900122446000E3004

    Trouble codes:
        P256300 - Turbocharger Boost Control Position Sensor Circuit            Range/Performance
            Intermittent
        P00AF00 - Turbocharger/Supercharger Boost Control "A" Module Performance
            Intermittent

For ACC, the error is:

   13 Adaptive Cruise Control

    System description: ACC BOSCH MQB
    Software number: 5Q0907572J
    Software version: 0654
    Hardware number: 3QF907572
    Hardware version: H10
    ODX name: EV_ACCBOSCHVW416
    ODX version: 002006
    Long coding: 2B0000C159FFC728949C810560400600000000000000000000

    Trouble codes:
        U112300 - Databus error value received
            Intermittent