The brief
Mr Wan called us because his Tiguan wouldn't engage gear, and asked for a tow in. A gearbox that won't engage is one to take seriously, so it gets checked thoroughly before any repair, because the obvious answer isn't always the right one. In most cases a gear that won't engage points at the mechatronics, the transmission control unit. But not always. The gear selector cable runs from the gear shifter to the gearbox, and it's what actually moves the box into the gear you've chosen. It's made of wire in a rubber casing, and over time the casing gets brittle and the cable can wear and snap, and when it does, the shifter moves but the gearbox doesn't, so the gears fail to engage. A snapped cable doesn't repair, so it gets replaced, which is a complex job done properly.
The diagnosis
A thorough check before any repair showed it wasn't the mechatronics this time, the gear selector cable had snapped, which is why moving the shifter did nothing at the gearbox. The mechatronics and the rest of the transmission were sound. That's a gear selector cable replacement, the actual broken part, rather than tearing into the mechatronics that wasn't the cause.
The work
The snapped gear selector cable was removed and a new genuine VW-spec cable fitted, routed correctly and the connections at the shifter and the gearbox set and adjusted so the gears select cleanly, every fastener torqued to the manual figures. The shift was checked through every position. A road test confirmed the gears engaging properly, selecting cleanly through the range, no fault codes, and the box behaving as it should, all turned around within a day.
The outcome
The gears engaging first time and selecting cleanly through the range, no fault codes, and the box behaving as it should, returned within a day. Mr Wan got the Tiguan back with the gears working. Checking thoroughly before the repair meant we replaced the cable that had actually snapped rather than the mechatronics, which is the difference between a cable job and a much bigger one.
