Richster

On the topic of this I had a new ABS fault develop which was due to the read nearside reluctor ring on the hub falling apart. IIRC i had a garage replace the offside rear a number of years ago. Solution was to fit a new hub which wasn't particularly tricky with the right tools but did need a lot of torque to get the bolt out. BTW on mine they were M18 spline, I've seen lots of information online about them being M16 sometimes. I also replaced the ABS sensor while I was at it and this fault went away. The traction control warning after about 10 mins is still an issue though (even if going nowhere!) I'm likewise increasingly thinking it might be a fault with the ABS unit itself.

Thanks yes I'll probably get this scanned at a garage. I had a friend look at it with VCDS full version, if I recall correctly he mentioned the ABS module disappeared for no obvious reason partway into the journey. The sensor readings for the 4 wheels seemed normal. Agree moisture is the cause of the ABS + traction on startup, but the traction switching off after 10 mins (ish) running is an odd one, I don't think it's related.

I should have updated this way back..... EML light issue was indeed a combination of two things: glow plugs needed changing EGR valve was faulty (wouldn't open under vacuum, assume leaking) Still ABS issues but the EML is resolved. Thanks to all who have me given me thoughts/input here.

I have a strange one with the traction control warning..... The yellow warning light on the dash consistently comes on after about 10 mins of running the engine from cold (just the traction control warning, not the ABS warning). Note that I don't need to move the car - it will happen when sat on my front drive. It's impossible to turn it off with the button on the centre console. Solution is to 'reboot' the car. From testing the ABS still works even when this is 'on' Sometimes on startup the ABS and traction control lights do come on immediately, this is generally when the car is wet and it will normally resolve itself once dry. Things I have tried (these sound unrelated - but I've read they can cause these kind of symptoms) New battery - it was overdue! Changed the MAP sensor (no change) Changed the MAF sensor (introduced all sorts of problems, probably a low quality aftermarket part. I refitted the original one...) I did change the EGR valve a few months ago which was indeed faulty, that did resolve an EML warning I was getting routinely. Any thoughts gratefully received!

Update.... I got the car through it's MOT with no waning light issues. The EGR issue may / may not come back after yesterday's valve clean up, will keep an eye on that. I slipped the garage an extra £10 and they kindly hooked it up to their own diagnostic equipment. Fault reported on front driver side ABS sensor so will swap that out. I would think the wiring harness is also worth a check here. Today is a good day!

I can't scan it with the version of VCDS I have (doesn't recognise it). I'm not sure if it's because I have the free version or it's an Octy Mk 2 which I don't think is supported. May be worth asking a garage nicely. ABS works fine mostly (tested it with a few emergency stops), I think the issue is likely an intermittent reading from one of the sensors. My suspicion would be the one which was replaced before. Some more research suggests the lite version of VCDS can only read the engine module. Probably I'm best off asking a garage nicely rather than splashing the cash on the full version.

I can't scan it with the version of VCDS I have (doesn't recognise it). I'm not sure if it's because I have the free version or it's an Octy Mk 2 which I don't think is supported. May be worth asking a garage nicely. ABS works fine mostly (tested it with a few emergency stops), I think the issue is likely an intermittent reading from one of the sensors. My suspicion would be the one which was replaced before.

In an attempt to solve the EGR fault, today I took out the valve and gave it a good clean out (the port at the bottom where the exhaust gases enter was full of gak - non technical term). The valve definitely moves freely now (I could push it up with a screwdriver) though can't confirm if the vacuum system is working correctly. When I test drove it I noticed a kind of squealing sound from leaking air when accelerating hard which may have been some trapped dirt? After a few hard accelerations the issue went away. If anyone's looking to do this - it's not particularly tricky to get the valve out, but there's very limited space to work with hex keys (2 sizes needed). Moving the duct out of the way behind the engine helps a little. I could get a replacement valve for not much, but I'm not sure that's the root cause of the issue. I still see the P0401 insufficient flow message in the diagnostics, though the engine management light didn't illuminate. I'm confident after a reset it will stay off long enough to get through the MOT. Meanwhile the traction control tends to illuminate randomly during a drive. VCDS lite doesn't give me any specifics on that (I'm not sure I can read all the modules, I notice the 'auto scan' feature only mentions the Octavia MK1, not the MK2). Restarting the ignition clears the error. The rear offside sensor was replaced maybe 8 years ago, I'm thinking it could be related to that? How would I get this diagnosed? Ask a garage?

I haven't run the engine since the last drive when the error popped up. I just measured the battery voltage with a digital multimeter - 12.1V I think it's not more than a year or so old. I do get through them due to not using it much! It's a Bosch.

Not particularly -= but I rarely use the car as I WFH. After not using the car for a long time, I drove it about 20 miles. The light waning light came on during the return journey after about 5 mins. I've also been keeping the charge topped up from time to time when not in use.

Thanks for the info on the Passat So I stand corrected - I am no longer seeing plug errors. From a check just now: 005712 - Powertrain Data Bus: Missing Message from Instrument Cluster P1650 - 000 - - Have seen this before, I thin this might be somewhat of a red herring from what I've read elsewhere 005697 - Shareware Version. To Decode all DTCs P1641 - 000 - Please Register/Activate Internet tells me this relates to air con? I know the system isn't working (has a gas leak) but surprised this causes a 'fault' 001025 - Shareware Version. To Decode all DTCs P0401 - 000 - Please Register/Activate Internet tells me this is an EGR valve issue - seen this a while back. I think there is a function in VCDS for testing the valve, I don't know if that works in the free version I have. That's probably a good next thing to try. May just need a clean up? 005379 - Load Signal from Alternator Term. DF: Implausible Signal P1503 - 000 - - Not seen this before..... suggests alternator fault or fault with ECU -> alternator wiring having read other posts on here. Surprised to find this showing

Apologies - have updated year in my profile. It's a 56 plate - MkII, 1.9TDI I'll run the diganostics again (since I changed the plugs and the engine management light came on). Is it possible VCDS lite is giving me misinformation? I'm expecting to see the same fault codes. Will post here.... Re faults about specific plugs/cylinders, there's a rubber harness which connects them all together - it looks like the connection is common to all 4.

Hi - I have had an issue with my engine management warning light for the past few years, though if I reset it (using VCDS lite PC software) just before the MOT it will stay off long enough to pass! The engine seems to run perfectly in general. When looking at fault codes, the diagnostics (again VCDS lite) shows glow plug faults on random cylinders. I plucked up the courage to change the plugs which was surprisingly easy (it was still on the orginals, mileage is IRO 130K) and thought I'd fixed it, but the light is back on. After a reset, I can normally drive for about 30 mins or so before the engine management light illuminates. Normally this happens an engine restart or two after I reset it (maybe after there are a certain number of faults logged?) I also tried changing the glow plug relay previously, but that had no effect. I'm beginning to think the issue might be something entirely different? The other fault which pops up in the engine diagnostics from time to time reads something like databus drivetrain missing message from instrument cluster. The other intermittent fault I have is with the ABS, which seems to be somewhat weather dependant. Sometimes the ABS and traction warning lights illuminate, other times just the traction control. An engine restart generally clears these, but they can pop up a few minutes later. Does anyone have any thoughts? Or perhaps someone local has some better diagnostic equipment and would be willing to assist for a beer or two? I'm in Watford/Bushey area Both of these are MOT failures but I can usually get them to be off for the duration of the test. Thanks