Totally bewildered just found this post.
I have a Man Tgl 7.15 which I purchased 2 years ago for private use for chassis swop for old daf 45.
Never turned on tachometer because only private use.
Yesterday getting tacho malfunction and on board computer malfunction signs on screen as well as permanent engine management light and hazard light on screen.
Been quoted £1500 for new tacho plus calibration.
Is anyway it can just be disconnected Been told has to be on vehicle but I notice you can fill out exception form for testing.
Big Truck:
There is a factory near Budapest dedicated to manufacturing “black boxes” to disable digi-tacho without messing up truck electrics.
Was told EVERY truck running in Hungary/Romania has one fitted!!!
Hi I’m in Tauranga NZ and I have the same problem with my 2011 Mercedes Axor. It went to MB for a gearbox repair and now every time the truck starts moving (like 20-30 times a day) it comes up with a VDO TACHOMETER error on the driver dash. When the error is there you lose the truck digital speedo display and only have the analogue speed meter, Looks tacky and annoying. I’ll try to post a photo. I’ve lived with it but am now selling the truck so keen to get it sorted for the new owner. NeonGreen if you get this message and have a solution could you email me Medworx@xtra.co.nz Cheers, Terry
I’ve tried to get MB to sort but they have not seen this before (because it is a Euro Import) and each time I’ve gone to take it back either the technician or Scan Tool hasn’t been available, so I’m keen to either fix it myself or give them some insight on a solution. Cheers
Horsebox owners in the UK experience similar issues. The internal battery will cause all sorts of problems if it goes flat: the automated gearbox will throw a wobbler without a speed signal and the vehicle cannot pass roadworthiness inspection without a functioning speed display, it will also often trigger an engine mil light or emissions warning. In normal circumstances the battery is changed at recalibration time. Take the truck back to the MB dealer who did the gearbox repair and ask them to contact Germany for recalibration instructions. If the battery is left completely discharged for several months then the tacho can be scrap.