VitesseEFI

Dodgy cable/connection on the main feed wire? Or same on the engine to chassis earth strap?

Does sound like the pick-up strainer/gauze could be partially blocked. The erratic readings at higher rpm imply pump cavitation. Needs urgent investigation.

That is this system which VAG refer to as “ dynamic oil pressure” (DOP) which does use two switches. https://www.vwt4forum.co.uk/threads/flashing-oil-pressure-warning-problems.109439/ This is the system I was fighting in our old Arosa - not sure it’s valid for cars later than early 2000s, but I suspect there are still two switches. The light coming on with 5 mins of a cold start is not because the oil is hot and thin. Possibly because it’s cold and thick and the gauze on the pump pick-up is sludgy - which is a known issue on some VAG engines. More likely instrumentation but needs verification as already discussed!

I’d want to start by determining whether I’m chasing an instrumentation fault (the light telling lies) or a real problem. The only sure way to do this is to temporarily fit a mechanical gauge (into the hole where the switch normally goes) and measure the actual oil pressure. If it’s a real problem then I’d be inclined to suspect a clogged oil pickup strainer because the oil will be thicker when cold. However, I think it more likely it’s an instrumentation fault, and not necessarily the switch. I fought a similar issue on my son’s Arosa a few years ago. Checked the oil pressure with a mechanical gauge first, which was fine. Swapped the switch, which made no difference. Unfortunately VAG seem to have made it more complex than needed - there was quite a bit of electronics involved, none of which seemed to be broken, but it still turned the light on whenever it felt like it. Ignored it. After a while (months) it stopped doing it. Odd.

Sounds positive. Fingers crossed! Garage deserves credit for taking the hit on costs.

If it’s still working at top speed then it’s more likely the resistor pack than the motor. The crunchy reverse gear engagement and baulking into first suggest that the clutch is dragging at times rather than a gearbox problem. Where are various reasons this might happen. In a car that is lightly used and maybe stands for days at a time it’s possible that there’s a bit of rust on the gearbox input shaft spline stopping the clutch driven plate sliding smoothly on it, meaning it doesn’t always fully release.

Vacuum leak somewhere? Any check engine light?

Thanks Mike. I’ve not done any physical investigations so far. Only the VCDS trawl. I suppose the only physical thing done was the ABS pump “exercise” routine, which does make your second point entirely valid, though I don’t think the car has done much sitting around I do need to go round the brakes corner by corner to check the mechanicals and also do a full fluid change/bleed. I do usually do this because with any car added to the fleet but I’ve been a bit slow on this one due to its apparent decent history and competition from other fleet members!

Traction control now working too. Pleasing, but most odd…… Got me wondering if I’m loosing the plot!

Well, seems that since exercising the ABS pump, the ABS system at least is working normally. Not completely convinced about traction control - further testing required.

Bit late to the party but just to say that I also think this is a timing issue. They are pretty fussy about it. Different animal I know but have had a very similar problem on a 1.9PD which was completely fixed by simply re-timing it. Also of note was that the timing kit I borrowed for this had several combination of tool that appeared to fit but only one that was actually right! Working out which was the chore. Also have to wonder when they are apparently happy to quote £4k to change the pulley which they previously thought was ok..... especially when (as Alasdair has already pointed out) the pulleys are really not expensive. Good luck!

Thank you all so far. Managed to get the elderly and very canterkerous laptop that my VCDS lives on to work long enough to interview the car properly. Very few codes overall (mostly relating to low voltage and intermittent CAN communication issues) and none at all relating to ABS/TC. Full scan attached -it's wonderfully boring! Logging the output from all 4 wheels showed them all to be working and in agreement speed-wise. Doing the output test on the ABS pump provoked a reaction for each corner (pedal vibrates during the "unlocked" part of the test for each wheel), so I'm at a loss to explain why it wouldn't function normally. Will have to go and find an empty gravel car park to do some real world testing to make sure it's not me that's faulty! Scan-TMBHT21Z5C2023429-20260104-1420-185320km-115152mi.txt

Thanks. Will scan properly ASAP. Above seems unlikely as the lights do come one when the ignition is switched on. I know that in the past warning lights “confuser” boxes existed for fooling MoT testers, but in these days of integrated systems it’s probably easier to just fix the ABS problem! Car did come with a stray ABS sensor in the glove box (which measures open circuit), which does imply recent previous work….

Have an emerging issue with my 2011 facelift 1.6TDI. Generally a tidy, seemingly well maintained car. I’ve only owned it since the beginning of November and from quite early on I’ve noticed it seems quite willing to break traction in 1st gear, even second gear in damp conditions. Aside from the separate question of why a puny 1.6 has so much grunt, as I understand it the car has traction control and should be limiting torque to prevent this and also flashing the skid-mark sign on the dash. It doesn’t. If I press the ASR button the “skid” light lights continuously and it behaves in exactly the same way. More worryingly, last night I had to do a full-on emergency stop on a straight, dry road and fully locked all four wheels. No ABS action whatsoever. And yet, here’s the twist, no ABS or traction control warning lights. Though they do come on with the ignition and go out after a few seconds as expected. Also no codes, at least not with a generic reader. (Will look again with VCDS once I’ve convinced the laptop it lives on it’s not dead…..) Seems unexpected that two safety related systems (especially ABS) can be non-functional without any warning lights on - any ideas?

The implausible MAF reading was historical I think and only seen the first time I scanned it after getting the car. Cleared it and it’s stayed away over the last 1,500 plus miles of mixed driving. Fingers crossed it stays away. That said, I’m no fan of EGR on diesels, so curious to know about your EGR delete. Disabled in software but physically present, present but blanked off (gaskets with no hole) or completely removed and blanked off? I blanked off the one on my A6 years ago, which was very easy as it’s old enough that no software changes were needed. With that done and all of the soot accumulation cleared from the intake it picked up 5mpg average…. I realise software changes are 100% needed for this car. Even the ‘05 1.9TDI Octavia and 04 Audi A4 1.9TDI my sons have can detect blanked off EGR….