HELP- 2.0 tfsi management light flashing and doesnt idle correctly.

[Lewbo]

have a 57 plate a3 2.0 tfsi showing 39,000 just driving home tonight doing 40mph slowed down for roundabout as got round it and pushed the pedal the car started juddering and my engine management light was flashing, pulled over right away and 1st thing i noticed is that the revs were bouncing up and down just above and below 1,000 rpm. was 2 miles away from home so drove it back and noticed a power loss and felt like car was spluttering.
plugged my machine in and it came up with these codes,

00768- rear heater core temp sensor (g154)

00772 - 0.3 bar oil pressure switch (f22)

has anybody have these codes come up before, and what it is thats throwing them up, only had the car a few weeks. well pi**ed off.
does anyody know what could cause this and will it cost me lots of money just after christmas too.
all help is really appreciated as i need it fixing asap as its my only means of transport and back at work on next week.

 

[NHN]

clear the faults & see if they come back, if the oil pressure switch is faulty then fairly simple to replace.

 

[Lewbo]

thanks for quick reply
i have cleared these and both come back straight away after driving it again, where is the oil pressure switch located on the engine and do you have any clues as to what the rear heater core temp sensor is.
much appreciated

 

[Lewbo]

also forgot to mention when i put went into manual as its dsg, when i was above 2000 rpm there was no problem and pulled exactly as it has it should do its just below 2,000 rpm if this helps so when am in 'D' driving steady it does this.

 

[audicruiser]

I notice you have a k&n filter fitted. It could be oil from that caught in the MAF sensor causing wrong readings... I don't know if this effects the 2.0T but it did on the 1.8T 20valve engine...

 

[JST_A3]

This may help with the diagnosis of the first code: G154 Sensor - BRISKODA.net

As NHN suggests, the low oil pressure could just be a faulty sensor, have you checked the oil level?

 

[Lewbo]

thanks i came across that last night, maybe could change that then, yes i have checked the oil and it hasnt dropped but looking at the car today i noticed there is an oil leak so got underneath the car and noticed its quite high up behind engine, looks like it maybe the rocker cover gasket, would this cause the problems i am getting. the car seems worse today too. really spluttering.

 

[Lewbo]

just a quick update, as everywhere is closed as its been bank holiday weekend got bored sitting around so just thought i would check the spark plugs, as i pulled out the coil it was covered with what looked like rusty water, then when i took the spark plug out it was also covered in rusty water. check the rest and they was fine. so clean the plugs and coil up. when i started it again it was running just as it should, after 5 mins it started again. checked them again and they was still dry.
is it worth buyng new plugs and coils 1st before buying a rear heater core temp sensor ( supposed to be rear lambda sensor) then go from there?

 

[paddy]

Its possible if the coil has been sparking to the head because it was wet that you now have a track, a carbon line like a crack to the head which is an easier way to ground than through the plug.
Did the plug that was wet look any different to the others when you took them out ? How old are they ?

the rear lambda sensor just measures the efficiency of the Cat. front ones are more important but neither would give you a misfire like you describe from my experience but i am not a turbo bloke so i cant be sure. Certainly a failed lambda put up a engine light on my car but it didn't effect the running.
Plugs are always the first place to look in my opinion with a misfire and as your car is 07 you will do no harm changing them anyway as they are prob original. Get some iridium.

 

[Lewbo]

no the plug looked exactly the same as the others, the plugs was last changed 26000 miles ago.
do you reckon it would have damaged the engine having water on it.
well i will change the plugs and if theres no joy maybe the coils next.
if it is the plugs, why is it throwing errors up about a oil pressure switch and heater sensor.

 

[paddy]

I really don't know mate but if it was misfiring on that wet pot then that would poss set the Lambda sensor off as the mixture changed in the exhaust gas.
If you dont want to put it into Audi's then you are not wasting your money with a new set of plugs. Can you borrow a coil of anyone to see if that does the job ?
You will not have damaged the engine but it would be good to see where that water is coming from. If it was just condensation i would expect it to dry off once you start up.
If it misfires from start at tick over you could fire it up from cold for 15 seconds, switch of and see if you can feel one exhaust down pipe is cooler than the others ( carefully) and see if that ties up with the wet plug pot. If so i would guess its plug or coil pack.

 

[paddy]

Remember fault codes are not necessary the problem, they are just a pointer. If you have VCDS then your measuring blocks are your diagnostic tool

 

[Lewbo]

another update i just replaced the plugs and still the same but the revs are not jumping about as much but still the same, so did the coil pack test, went from left to right one at a time disconecting each coil and engine nearly cut out. came to the last one (one with water in) and it made no differnce in the engine what so ever. so swapped it round for another coil and did the same and changed to another cyilinder so it turns out its the coil pack so off to audi tomorrow to order a new one.

 

[paddy]

Cheers Paddy

No problem mate ....................

 

[NIC1985]

hey guys, im looking for some help I have an s3 57 plate and its doing exactly the same as this the revs are bouncing up and down from 100rmp to 2000 rmp but ive changed plugs and checked coil pack its nothing to do with those by the looks ive also done tested it by taking the coils off one at a time, but it gets worse the minute i take any 1 of them off.

I had it on the computer and it said ( heat temp sensor ) and ( idle fault )

I recently had the timimng belt done at an audi approved dealer and wondering if it could be anything to do with that, although it seemed fine until i dropped the oil and changed that for Castrol 5 30w
im baffled and confused which route to go down to find out what it could be????? hope someone can help be musch appreciated

 

[NHN]

Welcome.

Please show us the vcds proper full log of the faults.

Bouncing from 100-2000, or did you mean 1000-2000.

Have you actually replaced the coils or tested with a new one & swapped out of each cylinder to see if its 1 of these, as removing a coilpack will of course make it ropey as that cylinder isnt firing, need another one to rule out.

 

[BlueSpark]

There was a coil pack recall on the 2.0tfsi engines a while back now. Audi did it FOC a couple of services back now for me. Although i didnt have any problems with it before but might be worth a try if you havn't had it done already.

 

[NIC1985]

hey guys cheers for the reply's

thanks for the info sorry NHN i ment 1000rpm to 2000rpm ill buy a new coil and try rule it out that way, thanks bluespark tried that recall trick with the dealer but they said it wasn't that model,
do you not think it could be anything to do with the timing belt??? been changed

 

[NHN]

Well yes if the timings of it can cause number of issues, so get it checked out by a professional independent or dealer.

 

[NIC1985]

cheers mate, an audi approved dealer changed it so maybe ill take it to Audi for them to see if anything is wrong wi it
thanks for the help

 

[Demon110178]

Hi there I've got the same issue on my s3 the same codes have changed plugs and coil packs does anyone have the part number for oil pressure switch and any guides on replacing please