Hi all,

While I had a bit of spare time today, I decided to run an auto-scan on my 2018 Superb SEL (with DQ381 DSG gearbox) to check for any fault codes. One code caught my eye—it was related to the automatic transmission. There were no warning lights on the dash, so without the scan, I’d have been none the wiser.

Out of curiosity, I checked my dashcam footage and noticed the error appeared right as I came to a stop in traffic—coincidentally, just as Rick Astley came on the radio (not sure if that's a sign or just bad timing 😅). For reference, I have the start/stop system disabled.

Not knowing what the code meant, I turned to Google—and naturally, that led me down a bit of a rabbit hole and into a mild panic. That said, I’ve driven the car several times since the code first appeared and it hasn’t returned. The car feels completely normal when driving.

The car has around 63k miles on it, and I had the DSG oil changed at 42k as a preventative measure.

It's no longer under warranty, and I recall dealers generally don’t investigate issues unless a warning light is active. Still, I’m wondering if this could be an early warning sign and whether it might be worth having it looked at proactively.

What do you think?

1 Fault Found:
35494 - Control Circuit for Aux. Trans. Fluid Pump 
          P0C29 00 [00101000] - Implausible Signal
          Intermittent - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 0
                    Fault Frequency: 1
                    Mileage: 102195 km
                    Date: 2025.09.03
                    Time: 13:30:31

                    Engine speed: 742.00 /min
                    Vehicle speed: 0 km/h
                    Coolant temperature: 91 °C
                    Clutch: primary stat: Creeping
                    selected gear: GANG_2
                    Driving position: d
                    Engine torque: 4 Nm
                    Control Module temperature: 85 °C
                    Accelerator pedal position: 14.9 %
                    DTC memory status: 296

Edited 7 September, 20257 Sep by ffvrs

“Tested since memory clear”. I always see that meaning something went momentarily wrong but is fine. Slight signal outside range for whatever reason for a split second and back to normal.

Just clear it and see if it ever comes back. You have it documented here if you ever want to check 👍🏼

Yeah, I think the general consensus is to wait and see if the error comes back. I’ve spoken to several VAG specialists about it—some are aware of the issue and say failure is likely due to bolts holding an auxiliary pump working loose, falling out, and causing damage to the gearbox. Others, however, haven’t come across it at all.

Mine’s a DQ381, and from what I’ve gathered, this was a known issue within Audi/VW, where they would sometimes replace the gearbox as a goodwill gesture. Not sure if Skoda would do the same, especially since the car’s now out of warranty.

If the fault returns, I’m potentially looking at a £2,600 bill to replace the pump with an upgraded (and supposedly safer) version. Worst case, if it fails completely before I catch it, I could be facing a full gearbox replacement costing up to £7,000.

After spending so long finding the right Superb, I’m reluctant to let it go just yet. I’m hoping it was just a one-off glitch and doesn’t come back—but until then, it’s definitely playing on my mind.