J.R.

Ooops, silly me! Brain fade again! It does pause the intermittent wiping when you stop at traffic lights (or anywhere really) which is kind of neat. Plus the dribble wipe but both of these are commanded by the Body/Comfort control module.

I agree with what you say Pete from the info you have gleaned from the wiring diagram however having repaired the one on my 2006 MK2 Octavia a couple of times the only way I could get the motor to turn under bench test was by directly powering the windings, it also had large 12v and ground wires and the other two were twisted pair so my conclusion then and now was that it was a canbus node and I think it was even the last one with the EOL termination resistor. I can see a couple of things in your hypothesis that are worth reflecting on: An "intermittent function initiated" being a pull up to 12v does not take into account the differing pause times selected by the stalk switch, perhaps its a coded signal. "Wash wipe cycle initiated" The rear wiper does not control the washer pump and a wash wipe cycle is simply run at X speed for as long as commanded, why would that be a different input to the one for continuous wiper operation until input removed? What about the various wiper speeds and the tear wipe programmed function? I'm pretty sure on my MK2 all this was handled by the body control module and the relevant commands sent to the rear wiper module and the washer pump controlled by sending 12v or reversed polarity 12v to it. I could confirm by looking at the Gateway installation list on my Yeti, if there is nothing resembling the rear wiper motor then I was wrong. For sure the wiper motor and a lot of other equipment on the vehicle cannot be faultfound or tested in the traditional way of hotwiring things. I too would really like to know exactly how it works because its only a matter of time before the one on the Yeti plays up, the only saving grace being the lack of rain where I now live!

Alternator pulley one way sprag clutch. Look at the longer length of the auxiliary drive belt if it oscillates back and forth then the unit is foutu and the shaft is direct driven.

Thanks for the informations, every day is a learning day and may it continue to be so. My "opinion" not given with such unwaving certainty would be to suspect the sensor, if the person does not have access to VCDS to confirm its failure then my suggestion is to replace that first as it is cheap and easy, or bloomin expensive if you pay a dealer to do so. They have all been rusted in place some very much so but I am patient and persistent and as long as I keep my hand in have a good feel and ability to keep just below the material yield point. 5 minutes was enough for me, within a minute I would know if it was a lost cause and I would have to drill it out, swapping out the wrong hand sensor that I had temporarily fitted (bodged) with the correct one took 45 seconds.

There are no magnets in the ring. The sensor has a magnet and a hall sensor, when the "teeth" of the castellation pass the magnet it reduces the magnetic field acting on the hall sensor changing its output state. Failure mode is the sintered magnet fracturing from impact, in my case clipping a kerb. I have no idea why you are advocating Taff B to undertake the very difficult and expensive job of replacing the wheel bearing and trigger ring without knowing it is faulty when the ABS sensor can be replaced for a few pounds in a few minutes without even jacking up the vehicle. If the fault remains then for sure the trigger ring is likely to be the problem but any build up of rust can be cleaned out very easily while the sensor is removed.

The cynic in me doubts that the people with all the gear and no idea will be capable of or interested in re-aligning the front and quite possibly the rear subframes, they just seem interested in twiddling a few nuts and producing computer print outs. The garage should be capable of putting the subframe back in the same position it was removed either by using the service tools or common sense, I would be very worried that they want you to take it elsewhere. I did not need a Hunter rig to measure and correct the misalignment between my front and rear axles and the vehicle body, just a bit of DIY to attach a laser spirit level to the wheel rims and a cardboard target fitted at the B post and held in place by the closed door.

Yes there is a control unit, it is inside the wiper motor assembly, it is a Canbus controller, the motor is not switched in the way you think it is which explains the bench test enigma. The wiper column switch switches a small control current from the relevant inputs of the body control module/comfort control module or whatever yours is called, this then sends data signals via Canbus to the wiper motor controller (and others that have an interest) and the switching is done on the circuit board of the wiper motor unit. It will have 4 wires, a large core live and neutral and a smaller twisted pair for the Canbus data line, if there are others then its because that node activates other equipment in the vicinity like high level brake light, door lock etc. Its all about reducing the switching current of switches and control buttons etc and reducing to a minimum current carrying conductors running around the vehicle relying on local controller nodes. You cannot test the operation of the motor in the way you would have done on previous vehicles, it requires a complete reset or rethink of your learned diagnostic experience and that goes for pretty much all the equipment on the Octavia 2 and later vehicles, the rear wiper motor is a good one to cut your teeth on and learn from, it was what opened my eyes. With VCDS and an understanding of how the canbus controllers work faultfinding, diagnosis and testing becomes very easy.

Exciter? Do you mean the sensor or the castellated trigger wheel?

I could easily knock up something for the correct alignment of the reluctor ringbut it looks like the issue is getting the correct depth of the oil seal and reluctor ring and them being at 90° to the crankshaft axis because VAG did not fit a stepped counterbore. Good to know, thanks for the info.

I see no reason why a DSG should not be done in the same manner that I did mine, its safe in that you are not under the vehicle like you would under a lift and the gearbox does not have far to fall should things go wrong, better than lowering on a trolley jack because that is very unstable even if strapped on and it lifts the tall transmission a further 100mm + off the floor making it harder to extricate although there may be no need, it can just sit there while the clutch and flywheel are replaced. One esential tool or precaution to take is make sure the cross-member is refitted in precisely the same alignment otherwise the vehicle can crab alarmingly, don't ask me how I know!!!!

That is interesting! How much are they going for these days after Covid etc? Used prices have gone silly in the UK since Covid, they always were in France and remain so!

Why does engine need to be at TDC to replace rear main oil seal and what does the special tool look like/do? Is it for removing the seal? - I have handmade winkling tools for that or a shim sleeve to protect the inner lip being damaged during fitting?

Removing the combined gearbox and transfer box (78kg in my case) is a peace of pi55 if you think it through before proceeding. You will already have fitted an engine support beam to support the engine and transmission when the mounts are removed, a pair of ratchet straps around that will support and lower the gearbox and transfer box slowly and in complete safety by one person but its easier with two, one watching and directing the other lowering. I was in a pit and lowered the assembly onto a couple of timbers laid across it, if you want to slide it out sideways then you may need to lift one side of the car up higher, there is no need for a transmission jack. Regarding the EGR cooler I opted to fit a £99 emulator/simulator so that it no longer passes gases, this also means I no longer have to periodically clean the throttle valve and intake tract, no blanking plates fitted at present as the EGR is in the closed position, if the heat exchanger does eventually leak water, unlikely now there are no corrosive gases passing, then I will blank off the cooling pipes using the bits from the kit. That flywheel sound expensive, I paid €308 for a 3 way clutch kit with DMF and concentric slave cylinder including delivery from Spain, it was a LUK kit.

The volt drop from the modules active during the first 30 minutes after locking alone are sufficient to put the battery below 12.5v especially if you have done a short journey and the battery has not heated internally through charging. You want the battery to go into sleep mode yet still be able to open the doors with the electronic keys, that is precisely what it would do if it were functioning correctly, shut down all of the controllers aside from the alarm and central locking after no more than 20-30 minutes, it will not do so if any of them are still communicating so that is the root of your problem. As myself and others have pointed out multiple times replacing the battery would be as big a waste of money as would filling a car with fuel which has a hole in the bottom of the tank.

The very systems that you believe this well written software should protect are ones (amongst others) that are depleting the battery. Horse, water, drink.

Whoever "fixed" the fault by doing whatever they did was spinning you a line, they are held in place to a precise depth by a bolted flange and cannot be moved in or out without it fracturing., the copper cage exists only in his dreams as much as it would benefit from one (the sensors get seized in place by rust and usually break on removal) no manufacturer in the last 100 years has wasted money on precious metals to aid replacement of non moving parts. A completely different animal and there is still no calibration involved in manufacture.

It would suffice if you did no have a parasitic drain. Do you really want to spend whatever small fortune the so called "specialist" will rush you for to end up with another irreversibly damaged battery? I despair of modern vehicles

There is nothing to calibrate, they are very simple and reliable, a hall sensor activated by a magnet whose magnetic field is reduced when the castellation of the reluctor ring passes beside it changing the output state of the hall sensor. If the magnet is not cracked they either work or they dont (dead on arrival) much like a reed switch.

Mine cost €1.70 each including delivery from China, there are two types on my vehicle so I bought a few of each not expecting much of them, I fitted one to replace the dodgy sensor over 2 years ago and it is still working faultlessly. VAG price is probably double what the ECP ones are, you pays your money you takes your choice, I have endured decades of know it alls (the types who will pay a main dealer £200 to fit a £1.50 component they could do in 5 minutes without even jacking up the car) lecturing me about buy cheap buy twice, and yes on rare occasions that has been the case but not to date on car parts. The usual failure mode of these is the moulded in sintered magnet fracturing from an impact, either a mechanic wielding a hammer carelessly or clipping a kerb.

A VCDS scan will show logged details of all commanded alarm activations and what sensors triggered them including volt drop. It does however sound like these could be self activations from a failing internal battery leaking acids onto the circuit board, yes I know the garage claimed to have replaced the siren unit but being unable to silence the alarm is not normal function.

There is a whopping big clue right there!

A shame, there would otherwise have been an opportunity to exploit the situation, you may still think of one!

We none of us have had vehicles with so much extraneous complicated emissions control and electronic equipment. A faster warm up is desirable for emissions, fuel economy and driver & passenger comfort but the benefits of these systems are quite marginal over a standard wax capsule thermostat. The sliding sleeve water pump was a good idea but an Achilles Heel, they have replaced it with something even more complicated and flaky.

I dont know how to make it any clearer, backplates = stone shields, the protection plates chassis side of each brake disc. I never mentioned back brakes, the backplates are fitted to all 4 wheels front and rear axle, they rust and the mounting fracture making a scraping noise, it could be any one or more of them.

AKA stone shields.