Hi,

[This is an update to a thread ('Octavia Tdi Engine Cut-out') I posted on the General forum....]

THREE times now in 10 days my 1999 Octavia TDi engine has suddenly died. Sob!

First two times, cruising along in 4th / 5th, the oil-pressure lamp and buzzer came on, the engine lost all power. Third time (4th gear), battery warning light came on, then all instruments and engine died.

Each time I was able to pull over and re-start car almost immediately.

Interestingly, first and third time occurred within 100 yards of same spot on my journey.

Skoda dealer could find no fault : oil level fine, no fault codes showing on diagnostics, no indication of mechanical fault.

Helpful replies to original thread (thanks guys) suggested "fuel pump relay".

Any other ideas out there? (the fact that the fault hit me twice on same spot of road suggests to me that it's related to some magic speed/rev value...ECU fault?)

Any suggestions gratefully received....

awed

Something electronic related as it seems that the problems clears after turning on again (I assume the problem turns the engine off and it's not even idling - practically a reset which also may explain why no fault codes). So a connection or sensor.

I've ruled out that it's totally heated related as I'd imagine that you would have to have waited a good few minutes before starting again.

Does the road wher ethe problem occured twice before have an paticular characteristics e.g. up or down hill? Again this could contribute.

May be if you can get hold of a VAGCOM and have it connected, you can catch an error code when the problem occurs.

Not much help.....sorry.

Cheers.

Adrian.

Adrian,

Yes, the problem kills the motor entirely, not even idling.

No, the engine restarts fine after just a few seconds - 15, 20 secs at most.

The road is smooth and straight and very slightly downhill (but I hit much steeper hills on the journey).

I'm tending towards a faulty ECU. I read somewhere that there was a VAG-acknowledged ECU problem with some units, but that was about the ones on 110 bhp units (mine is a 90 bhp) and the sympton was stalling in neutral, so I dunno.

Cheers,

awed

Have you thought about phoning one of the the Lucas/Bosch diesel specialists that advertise in DieselCar mag ? Worth a phone call ?

If another trip to my Skoda dealer can't fix it, I'll take up that suggestion, cheers.

When you say the engine starts again after 15-20secs - does it not turn over at all during this period?

I still think it sounds like the fuel pump relay., having expierienced the same symptons and at speed.

For the cost of the relay I would just put one in regardless, as my occurences of said fault were never picked up by VW or Skoda, but cure the fault a new one did.

Cheers

Andy

ps outside lane at 70 ish at 5.30 am during the winter time is no time to have this occur....it is very scary.

Hmm, interesting things to mull over.

Happened again today...and guess what : it was at EXACTLY the same spot on my journey that it has happened on three of the four times....to within 50 yards, 15 mins into the drive.

Why would a fuel pump relay - or anything else for that matter - fail so predictably at the same spot at the same time on a completely normal road? (I'm not discounting the idea, but I am puzzled).

Matthew - as far as I can tell (I'm always a bit shaken) the eninge is totally dead when it happens; I wait just a few secs, and then it restarts first time when I turn the key. (And if it was temperature dependent, why would the engine re-start...and then carry on for the remaining 20 mins of the journey?)

Cheers! Determined to crack this soon...Not planning on any motorway journeys until it's sorted, for exactly the reasons you mention Andy!

awed

It could well be that if it is the relay it has chattering contacts, which then get hot and allows the contacts to part, thus cutting you dead, which then cool allowing the motor to restart.

The other way to try, is to perhaps go the opposite direction and see what happens around the same time. But then you may have uncovered something much more sinister and someone has a giant remote sender affecting your immobiliser, but that sounds total b******S.

Andy

ps...when my old Octy did the same, the AA man called found nothing, the car then packed up on its way to the dealer, when the dealer got to look at it they found nothing, even when test driven. It was only when I insisted they replace the fuel pump relay due to previous occurences with our VW vans, that the fault magically appeared, and guess what..never did happen again after the new relay was fitted.

Personally I think garages rely to much on info and diagnosis sent from the car, gone are the days of expierience and intuition

I knew I had seen something about problems with TDIs before; check this out from Honest John:

"Some TD 110s had a problem of stalling while coasting to a standstill from about 15 mph in neutral. The cure was to replace the ECU, but if the car was a personal import out of its 12-month pan-Euro warranty, the owner had to pay. This problem now seems to be coming back on high mileage TDI 110s. VAG acknowledges a fault with the ECU (038 906 018 BM) and specifies an upgraded unit (038 906 018 GQ) at

As Andy said, might be worth getting the dealer to replace the fuel pump relay.

Also could be fuel cut off solonoid misbehaving (although this may be part of the fuel pump relay now)

Another long shot is to post your problem on tdi club as you may find others have had a similar problem and know the answer.

Plenty of folks on there who really know their stuff...

good luck!

Thanks for all these ideas. Car booked in to garage for Wednesday, I'll mention all suggestions to the mechanics. And if I find a solution, I'll post it up.

awed

Matthew - checked out the TDI Club as you advised.

A lot of people there reckon the culprit is the "relay 109" - I believe it's actually

called "load reduction relay". The 109 is a number painted on top of it. Many posting to the TDi club describe symptons very similar to mine, so it's going to be my first line of attack when iI take the car in .

This could explain a loud relay-like clicking sound I sometimes here coming from the region of the instruments, though it seems uncorrelated with the cut-outs.

Anyone got any experience of "relay 109" - quite a notorious component apparently.

Adrian - yes, I read that on Honest John too. But the symptons are fairly different, so I don't think this applies to me...yet....

Any "relay 109" tips?

awed

Following advice above, I checked out and posted a question on the TDI club site.

Answer; "relay 109", the "ECU Power Supply relay". (I've seen it given other names too, so not 100% sure about this title).

Search the web for this (in conjunction with "VW TDI") . Oh boy, it's a beauty. Lots of hits....obviously another common fault which VW have preferred to keep schtumm about.

Fortunately, a doddle to fix, and cheap too.

My dealer (Bowling Green garage, Powick) fitted a new one for

I had this problem with my old Golf 3 TDi, sounds the same symptoms as you have had. I took the car to a VW specialist and while I was talking to the mechanic with the car ticking over on the ramp there was a click and it cut out. Funny thing you think you didn;t really hear it but some how you did. He said he had had the same problem before with a Passat, Changed the 109 relay, cost about

I also had this on my Octavia GLX Tdi. It cut out twice at exactly the same point on my journey home. It was the fuel pump relay that was at fault - Skoda replaced it with an updated model, so it must have been a recognised fault. I guess that, as it warms up at a particular point the contacts part and you lose the engine. Since it is a cheap part, try that first. It is the most likely cuplrit.

A few people have mentioned "fuel pump relay". But since having changed "relay 109" I have not had a re-occurrence of the fault in over 5 weeks (touch simulated wood-effect plastic). So in this case I think it really was "109" which was at fault.

The NEXT time I get random cut-outs I will however look at the fuel-pump relay!

Originally posted by Awed in this post

The NEXT time I get random cut-outs I will however look at the fuel-pump relay!

Come on Awed, be a little more positive. It won't happen again

just a thought if the oil pressure warning light is comming on could the fault lye in a faulty oil pressure switch if the ecu senses very low oil (just about to seize) it will shut off engine !

I understand your logic, but I don't think so : when I took the car in to the dealers, the technician started it up, yanked out relay 109, and bingo! all the symptons I saw occurred : oil light and buzzer on, engine died. As he reasoned, the oil light is simply a side-effect of the ECU itself being shut-down, not something which is causing the ECU to shut off the engine.

Incidentally, I found some other people suffering from the same problem on various other forums, including one chap who had posted to the Top Gear web-site "Duffers" section and whose VW Golf (petrol) kept dying. I told him of my experiences, and he practically wept with joy.....his dealer changed relay 109 and he too was sorted.

I advise, check the relay 109 in your own car : small and black = you may have a nasty surprise; large and silver = safe.

Where can I find it?

Damn, I knew someone would ask me that....

(I am told) the location varies with car year and model, but it's either on the "fuse panel" or "relay panel". I recommend you consult your manual or phone your dealer.

I was peering through the glass of the "customer lounge" so I couldn't see exactly what the mechanic did. He just demo'd the effect of tugging it out and I could hear for myself the buzzer coming on and the engine expiring. He did it a few times and read out the warning lights that lit up (oil and sometimes battery).

Sorry to be so imprecise!