Mk4 Weird error on trip odo after service reset

[VAG Fan]

Lately I've been getting a weird error on my trip meter after resetting the service interval on my Mk4.

The procedure for resetting the service indicator is:
Ignition off.
Press trip meter reset button and hold.
Switch on ignition but don't start engine.
Release trip meter reset. (Display now reads "Service")
Turn clock adjustment button clockwise (minutes). "Service" indicator disappears.
Ignition off.

Normally, the trip meter jumps to zero during the procedure, and after it's done, it returns to the same reading as it showed before the service reset.

However, lately, mine always adds the mileage from before the previous reset (fuel stop).

E.g.
I fill up the tank on 850 km and reset the trip meter.
I drive 420 km and do an oil service, then reset the service indicator.
Normally, the trip meter should show 420 again.
But lately, maybe for the last three services, it will now show 1270, which is the current 420 plus the 850 from my previous reset at the fuel station.
It's as though my ECU or cluster is always lagging by one trip reset, when I do a service reset. So it "pools" the current trip mileage AND the previously reset trip mileage.

Any advice?

[Ashveer03]

That's a weird issue. Lol

Was there any editing done previously via vcds or another scan tool to change the service interval frequency?

How often, time & Kms does it ask for a service?

[VAG Fan]

That's a weird issue. Lol

Was there any editing done previously via vcds or another scan tool to change the service interval frequency?

Hi Ashveer,

Indeed, weird!

No, I never changed the service interval frequency. Around 2018, Panic did delete a whole lot of errors using VCDS, after we had cranked the engine with the Diesel pump unplugged, to pump oil into a new turbo. But this odo problem only started much later, around 2022. I remember that I had forgotten the exact sequence of button presses for resetting the service interval, so I was trying different combinations (before I found the correct combination online). I think that's when the problem started.

How often, time & Kms does it ask for a service?

The interval itself works perfectly normally. It uses the normal 15,000 km or 12 months, whichever comes first. I've checked it in my logbook, and it does exactly what it should.

It's literally just the "trip meter memory" that's wonky. It always adds my previous tank trip when I exit from the service reset mode.

[Ashveer03]

Maybe U have unlocked a new feature which nobody knows about. Lol

Could be possible that certain sequences changed some adaptations. Best bet would be to have a look with vcds to check if everything makes sense or not

[VAG Fan]

Yup, agreed. I'm taking the tractor to Panic later this year for a front suspension refresh, and will ask him to check the trip recorders with VCDS.