Here's a head scratcher for all you amazing members here....

 

From the top.

 

2012 Octavia Mk2 FL TDI

 

Start up, select D and start to drive. Notice it doesn't change to 2nd (or is it 3rd if it pulls off in 2nd)?

 

Shift selector to manual mode to change but still no change.

 

Turn off the ignition and re-start. Fault usually clears completely but may occur again at next start, or may not.

 

Once cleared, can drive many miles with no problem. Shifts appear nice and crisp, rev needle drops quickly in the next gear, so no slippage.

 

On instrument, antislip and ABS warning show. I can clear but they return quickly. Also have a brake fluid warning (see page 33 owners handbook lower left side of page). Checked brake fluid of course - seems full. Fiddled with the float a bit pushing it up and down. Brake fluid fault disappeared for a little while.

 

The brake fluid symbol illuminates and goes out at various times whilst driving. Of course this is a nightmare because one must still stop and check, not just assume that because it was / is spurious fault that the brake fluid is still OK because it was OK before. I think that's the proper approach to warnings.

 

On VCDS no gearbox fault shown, but there is implausible signal coming from one or more wheel speed sensors.

 

Should I replace all the wheel speed sensors as a sensible starting point?

 

Should I take the VCDS into adaptation mode and reset the gearbox properly?

 

Thanks to everyone who has a moment to scratch your heads and apply some grey matter or experience to it.

 

Rich

Edited 31 August, 20232 yr by OctaviaVRS2
make clarifications

My 2005 DSG Octavia had similar problems changing gear when one of the abs sensors was playing up. It would lurch and suddenly change, or keep a gear until the redline. 

 

I guessed that because the car uses the abs sensors for calculating the speed, it didn't know what speed it was doing so the funny speed readings messed up the calculations for the gearbox and what gear it needed etc.

 

Sorting out the abs issues instantly sorted out the DSG, so I would start diagnosing your abs issues as a first port of call.

 

A diagnostic scan should point to whether it's a sensor, wiring or the magnetic ring in the wheel bearings that is at fault.

Check your ABS cables, particularly the one that goes down to the driver's front wheel, closely for any damage. Splits can hide on the inside of the curves where the cable bends.