Ok, this might become long winded, so apologies if that's the case -

I keep getting the code "17544 - fuel trim: bank 1 (add): system too lean" come up on my '02 Octy VRS. AUQ engine.

Ok, I've done the rounds (before any one comments) and I know that this problem mostly relates to either the MAF sensor, fuel pressure regulator, leaky vacuum hose, fuel pump etc - so to be clear, I'm not asking for help/pointers on what the problem may be.

My question is based on the frequency of when the engine management system runs the particular diagnostic cycle that would give that code. To explain.......

I've only had the car 5 - 6 weeks now, and the garage have agreed to rectify the problem under warranty. (Fair play). But because it's such a long and varied list of what "could" be causing the problem, they're working their way through the list and then giving me the car back to test.

But lo and behold the engine management light keeps coming back on after 2 days or so, and approx 100 - 150 miles (give or take - depending on when I actuyally notice it's back on and remember to take the odo reading) - I then go back to the garage, they clear the code, have a fiddle, and then 2 days later and another 100 - 150 miles ish, it's back on.

So does that "every 2 days"/"every 100-150 miles" ish have any significance to what's going on to cause the 17544 code?

There's no other pattern going on, as it can either stay on when I first start the car, come on while I'm sat waiting on a garage forecourt, come on while I'm sat doing 70 on the motorway.......

Any ideas?

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I thought it worked from on/off cycles of the engine.

Unless you've got something getting to hot and then cold pops up.

You need to look at readiness as well as the fault codes. The readiness of an engine subsystem depends on the engine being operated for long enough that a full range of measurements are made by the ECU OR diagnostic tests are performed which ensure readiness.

You need to take it somewhere that doesn't just look at a fault code and replaces parts hoping they'll get lucky. You need someone who can diagnose the faulty component, replace it and then test that the problem is fixed.

You need to take it somewhere that doesn't just look at a fault code and replaces parts hoping they'll get lucky.

Never a truer word spoken! Lol. Trouble is the garage are doing it under warranty, so going somewhere else is going to cost me ££££'s that I shouldn't have to be spending - and then hope I can claim it back.

I do the same journey day in, day out. They can clear the codes on a monday morning on my way to work - I can then drive to work (35ish miles) and back (another 35ish miles) on that monday, drive back too work tuesday (another 35ish miles), and then it comes on on my way home tuesday afternoon.

Give or take the odd trip to the shop, or popping down the road to see friends/family, that cycle never changes.

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Just a quick update...... as the garage have now made the problem a whole lot worse!

Their mechanic changed a small vacuum hose that runs from the top of the fuel pressure regulator to somewhere on the bottom side of the inlet manifold...... but now the car runs lumpy, miss-fires like no one's business, erratic idling rpm, bugger all power, and a gastly hissing noise coming from a small white in-line one way valve under the inlet manifold....... Plus still showing the 17544 fault code, and also a whole load more now to do with the miss-firing and the fluctuating idle rpm etc.

The garage are now starting to get cold feet about fixing it, and I have a funny feeling they're going to do the off and tell me it's not their problem.....

Someone out there in Briskoda land must have some good ideas that can help narrow down the search for the problem (that isn't going to cost me big ££££££'s).?

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It sounds like a breather hose problem to me. Buy your self a tin of carb cleaner from the quid shop, remove the engine covers and with the engine running spray all the hoses with carb cleaner under the inlet, if the car runs worse, cuts out etc.. Theres your problem

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If you follow the hose back from the one-way valve, does it lead back to a valve on top of the charcoal canister (next to the coolant reservoir/power steering reservoir)?

If so there maybe a problem with the N80 purge valve on the canister which can cause this error.

If you follow the hose back from the one-way valve, does it lead back to a valve on top of the charcoal canister (next to the coolant reservoir/power steering reservoir)?

If so there maybe a problem with the N80 purge valve on the canister which can cause this error.

I'll check.

I think that the one side of the one-way valve runs to a small metal pipe that then goes to a rubber hose to the air intake near the afm, and the other side goes to a Y tube, but not traced it any further than that.

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