A2 2002 1.3 petrol intermittently goes into limp mode - then it is okay after re-starting???

[LucindaLee]

This fault has been bugging me for ages - for no obvious reason the car suddenly goes into limp mode. When this happens, I have to pull over to stop the car and turn off the ignition, wait a few seconds then start up again and then it drives fine until the next time which can be soon after or not at all until another time driving it - but it still has engine warning light on which sometimes even disappears until the next time. Our mechanic cant seem to find a solution as the fault is weirdly intermittent - the car will drive and run with no problems - he even kept it drove it for 2 weeks and frustratingly had no problem.

Looking for signs of when it will happen; I notice that the engine starts to go a tiny bit 'lumpy' when driving and then sometimes it happens after I have turned left and onto a slightly downhill road (same location a few times) and other times driving normally on a straight road while keeping a steady speed.

Really annoying as this A2 has low mileage 72k, otherwise it is in good condition - just can't trust it on main roads or long journeys until it's fixed and don't want to give up on it.

 

[Andrew]

Good Afternoon Lucinda,

Your mechanic will no doubt have run a diagnostic scan but without the results we are largely in the dark and it's a guessing game. @Teresa in Norwich will scan your car and list it here..

Free Scan Register

This is a register of members who generously offer free scans for other members. To arrange a free scan: 1. Click the pdf map in the footer and choose a location. 2. Cross reference the location number in the table below to identify the member. 3. Click on their username on the left, click...

www.a2oc.net

Very good description of your woes by the way.

Andy

 

[damadgeruk]

Andy beat me to the answer. Hope you get your car back to full health soon.

 

[steve_c]

I'm also in Norwich and have full VCDS. If you can get to me I can do a scan pretty much any time.

 

[LucindaLee]

Good Afternoon Lucinda,

Your mechanic will no doubt have run a diagnostic scan but without the results we are largely in the dark and it's a guessing game. @Teresa in Norwich will scan your car and list it here..

Free Scan Register

This is a register of members who generously offer free scans for other members. To arrange a free scan: 1. Click the pdf map in the footer and choose a location. 2. Cross reference the location number in the table below to identify the member. 3. Click on their username on the left, click...

www.a2oc.net

Very good description of your woes by the way.

Andy

Thank you Andy. Our Mechanic now 'hates' our car out of frustration! The car has been scanned many times - there was a problem with overheating as well but that has been fixed, he has also tried internet research but he is still in the dark. Hopefully if Teresa has more specialist experience with A2's the fault might be able to be identified and fixed - fingers crossed!

 

[kp 115]

This fault has been bugging me for ages - for no obvious reason the car suddenly goes into limp mode. When this happens, I have to pull over to stop the car and turn off the ignition, wait a few seconds then start up again and then it drives fine until the next time which can be soon after or not at all until another time driving it - but it still has engine warning light on which sometimes even disappears until the next time. Our mechanic cant seem to find a solution as the fault is weirdly intermittent - the car will drive and run with no problems - he even kept it drove it for 2 weeks and frustratingly had no problem.

Looking for signs of when it will happen; I notice that the engine starts to go a tiny bit 'lumpy' when driving and then sometimes it happens after I have turned left and onto a slightly downhill road (same location a few times) and other times driving normally on a straight road while keeping a steady speed.

Really annoying as this A2 has low mileage 72k, otherwise it is in good condition - just can't trust it on main roads or long journeys until it's fixed and don't want to give up on it.

Hi LucindaLee,
Can you recollect what the weather was like when you’ve had issues with the car?
the early 1.4 petrol cars had misfire issues related to the single coil pack breaking down.
Only visible by removing said item or looking on a damp/foggy dark evening for arcing.
Hope that is some help
Keith.

 

[LucindaLee]

Hi LucindaLee,
Can you recollect what the weather was like when you’ve had issues with the car?
the early 1.4 petrol cars had misfire issues related to the single coil pack breaking down.
Only visible by removing said item or looking on a damp/foggy dark evening for arcing.
Hope that is some help
Keith.

Hi Keith

Thanks for the feedback. I can only recall that over the past 6 months - ie in the summer and dry when it's happened - for instance it did it to me this morning!

 

[kp 115]

Hi Keith

Thanks for the feedback. I can only recally that over the past 6 months - ie in the summer and dry when it's happened - for instance it did it to me this morning!

So it was sunny & warm there, I had fog & showers in Lincolnshire & Cambridge.
The misfire count is monitored by the ECU & at a predetermined number it will cut fuel to that cylinder to prevent damage which then resets when the ignition is turned off/on again

 

[LucindaLee]

Hi Keith

Thanks for the feedback. I can only recall that over the past 6 months - ie in the summer and dry when it's happened - for instance it did it to me this morning!

Hi Keith -Thank you for suggesting to look at that type of fault. Unfortunately it's been covered, I just checked with our mechanic who said he has checked that fault and also the code hasn't come up : (

 

[Tomscar]

Hi Keith -Thank you for suggesting to look at that type of fault. Unfortunately it's been covered, I just checked with our mechanic who said he has checked that fault and also the code hasn't come up : (

Hi LucindaLee ... (2002 1.4 BBY) mine had an intermittent limp mode eventually diagnosed and fixed by replacing the ABS sensor on the back right wheel ... I would get the engine hesitating and not show any codes although a definite fault code showed when the sensor failed.

 

[audifan]

Well Lucinda, you are here asking for help. Have someone perform a full VCDS scan and see what that produces. You may have faith in your mechanic but we very probably have far more experience with A2's. Rather than run back to your mechanic who then tells you "tried that" take the scan result to him - along with any recommendations the person who scans the car has, or others from here.

Steve @steve_c would be a better choice for a scan and can help you.

 

[PlasticMac]

1: Get an A2OC member to do a full scan with VCDS.
2: Post the report here.
3: Get practical help, based on the scan, from experienced fellow owners, and experts.
4: Share with your mechanic.
Mac.

 

[Teresa]

Thanks for all your help folks. Between us @steve_c or I will do a full scan and post results. I have spare 1.4 coil packs somewhere if it ends up being an errant one. Hopefully we should be able to fix it

 

[Robin_Cox]

Appreciate that it may not be possible, but if you say that the misfiring problem tends to occur with a specific set of road conditions, if there is a way to drive with @Teresa or @steve_c and a computer as a passenger on that road in the event that the problem recurs when they can scan immediately it may give some clues that won't be otherwise detectable. If your mechanic didn't drive the same roads under the same conditions as you do when it happens it may be that the issue simply wasn't being provoked.

Our AUA (52 plate 1.4 petrol)-engined car also had a recurrent misfire issue 2-3 years back. To begin with there was just the occasional slightly rough running or sporadic engine light. This started to happen more often until eventually my other half was driving a car with 2 working cylinders (full throttle) for a mile or so on the local dual carriageway until she got off the slip road, stalled and restarted on all four at the roundabout, and then returned home with the light on. I was able to reset the light but the misfiring became endemic. Eventually I found that the coil pack itself was completely goosed - cracked casing, defective insulation on the rear - but this wasn't visible until the whole thing was removed. New Bosch coil made probably the biggest difference to the way the car was running (never had a misfire since pretty well). I'd also replaced plugs, leads, injectors, throttle body and EGR (all were extremely worn) previously but the coil was the main problem. Lambda and cat also ended up being replaced, probably secondary to constant passage of unburnt fuel into the exhaust from the misfiring.

 

[steve_c]

Really annoying as this A2 has low mileage 72k, otherwise it is in good condition - just can't trust it on main roads or long journeys until it's fixed and don't want to give up on it.

When I bought my A2 in 2016, it had a pretty similar mileage to yours, and suffered similar problems. Sometimes it would go into limp mode, occasionally cut out entirely, with no obvious cause.

There actually seemed to be a cocktail of causes, and I worked my way through dealing with them.

The battery in the car was the original one from when the car was sold new. Testing the battery suggested that it was still in reasonable shape, but when I replaced it with a new one, the car immediately ran better and my mpg improved.

The iignition leads and spark plugs needed changing. I have the AUA engine in my car, which has the single coil pack unit and four separate ignition leads. The ignition leads were the ones that had been fitted from new, and when I attempted to get them off, I found that they were perished and falling apart. So a new set of genuine Bosch leads was a necessity.

I haven't needed to change my coil pack, but will shortly be doing so anyway. The experience of others here suggests that cheap coil packs are a waste of money, and that Bosch is again the brand to seek out.

I had a new exhaust made in stainless steel. The original exhaust had rusted quite badly internally, and it seemed more straightforward to just replace the whole thing and be done with it. And from that point on, I had no more ongoing problems, the car was back to running as it had when new.

There is a more recent issue around fuel since the arrival of E10 petrol. For a variety of reasons, I have used 99 RON E5 fuel for quite some time, but the new standard E10 petrol is less stable than the old E5, and for cars like ours doing low mileages there is a strong case for switching to a premium fuel.

So there's some things to think about. We don't of course know whether your car has the early AUA or the later BBY engine (2002 is right on the cusp) and it would be helpful to know which you have.

 

[Proghound]

it would be helpful to know which you have.

You can tell from the sticker in the front cover of your service book, or there's usually another one somewhere in the battery compartment under the boot floor. Included in the more prominent codes towards the top of the sticker will be either AUA or BBY.

 

[Teresa]

So lovely to meet Lucinda and her lovely chap on Saturday.
Here are the results of the scan.
The Abs sensor light was flashing (and had apparently not done that before), so I did suggest taking the drivers side wheel off and checking if the wires had worn (my 1.4 had previously had similar issues and that was the problem there).
@LucindaLee - how was it on the way home? Did you manage to have a look behind the wheel?

 

[steve_c]

Here are the results of the scan.

Teresa, I'm not clear whether you just scanned the car once, or whether, after the first scan and the clearing of the faults, the car was taken for a short drive and then rescanned?

Although given there are so few faults it's not the end of the world.

I can see that this is a 2003 model year car.

Fault 17961 is the issue that is causing the car to go into limp mode. Barometric / manifold pressure signals implausible. I suspect that one of the valves is sticking intermittently.

When was the air filter last changed?

The EGR valve may need cleaning.

What oil is being put into the engine on its annual service?.

If the fault remains intermittent, Lucinda probably needs to switch to Shell V-Power and drive in a lower gear.

 

[Robin_Cox]

Teresa, I'm not clear whether you just scanned the car once, or whether, after the first scan and the clearing of the faults, the car was taken for a short drive and then rescanned?

Although given there are so few faults it's not the end of the world.

I can see that this is a 2003 model year car.

Fault 17961 is the issue that is causing the car to go into limp mode. Barometric / manifold pressure signals implausible. I suspect that one of the valves is sticking intermittently. When was the air filter last changed?

If the fault remains intermittent, Lucinda probably needs to switch to Shell V-Power and drive in a lower gear.

What oil is being put into the engine on its annual service?.

We also had intermittent 'barometric / manifold pressure' errors. Suggestion here was to start with replacement of the oil filler cap on top of the rocker cover (the simplest replacement as well as a petrol filler cap before moving onto more involved fixes) - which was visibly surrounded by a ring of oily soot. New cap with a seal that is flexible and able to maintain the lid pressure against the lip underneath have stopped that error from happening.

 

[steve_c]

We also had intermittent 'barometric / manifold pressure' errors. Suggestion here was to start with replacement of the oil filler cap on top of the rocker cover (the simplest replacement as well as a petrol filler cap before moving onto more involved fixes) - which was visibly surrounded by a ring of oily soot. New cap with a seal that is flexible and able to maintain the lid pressure against the lip underneath have stopped that error from happening.

Yes, very sensible advice as always, Robin. I suspect that the OP uses a general garage rather than a VAG specialist to service her car, and these are the sort of things that may well get missed.