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Audi A2 1.4 AUA 2001 - Codes 65535 & 17566, possible ECU fault? - Fixed #

Posted by Lee Hemmings on November 7, 2012, 8:30 am

Year of Manufacture *: 2001
Engine Size and Code *: 1400 aua
( Optional) Fault Codes: 65535 and 17566

Car as above fault codes, 65535 says system ok-(if mil activated check ecu)
2nd code is map sensor implusable signal, i have scoped the map sensor itself and the plug and ecu and all is good.
5 volts and earth are good, also volt drop tested all 3 wires with ecu disconneced and 00.2 drop is well within spec- for me all pointing to ecu, but my problem is that camco in warrington say cant bench test it above 200rpm due to immobiliser. BBA reman have never tested one but ask me to send it to them and they will see what they can do, but i dont think they can do alot with it due to the immobiliser!!
Any one had this fault or any ideas ?

Re: audi a2 ,- Poss ecu fault

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on November 7, 2012, 9:28 am, in reply to "audi a2 ,- Poss ecu fault"

Lee

Apart from the code,s what exactly is the fault.What are you reading the codes with ? Any freeze frame data at the time of the fault ? Have you cleared the code,s and they have come back etc.

Kev.

Re: audi a2 ,- Poss ecu fault

Posted by lee hemmings <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3416' width='330' height='300' border=0 style='border:none;'> on November 7, 2012, 10:20 am, in reply to "Re: audi a2 ,- Poss ecu fault"
Lee Hemmings

Hi Kevin, i am using vagcom, the fault is only the light is coming on, and tghe car drives really well.
Yes i have cleared them and yes the 65535 comes back every time and the map one comes back every other time ....

Re: audi a2 ,- Poss ecu fault

Posted by andyhyoung <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on November 7, 2012, 2:29 pm, in reply to "audi a2 ,- Poss ecu fault"
Andrew Young

I think I would be looking at a poss mechanical problem here.Have you checked the cam belts for excess slack?

Re: audi a2 ,- Poss ecu fault

Posted by Lee Hemmings on November 7, 2012, 2:55 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Message modified by board administrator November 8, 2012, 3:13 pm

Hi Andy know i have not, why would think its a mechanical fault and even more so cambelt tension ?

Re: audi a2 ,- Poss ecu fault

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on November 7, 2012, 4:39 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Kevin Apps

lee

"Hi Andy know i have not, why would think its a mechanical fault and even more so cambelt tension ?"

If Andy had not asked the question i would have!

Kev.

Re: audi a2 ,- Poss ecu fault

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on November 7, 2012, 5:26 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Mark Carter

Hi Lee,

What is the MAP reading? How is it generated? and what sort of things could cause it to be out of spec?

Mark

Modern cars, Its all wizardry and witchcraft

Re: audi a2 ,- Poss ecu fault

Posted by lee hemmings <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3416' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 8:22 am, in reply to "Re: audi a2 ,- Poss ecu fault"
Lee Hemmings

Ok i did not check cambelt tensioner as i think i would have had other systoms like noisey belt area etc, if timing out then misfire!So please feel free to elobrate on this, if anything just to learn from.
Then i did check and all is ok in that area.
Mark its generated with vac on the manifold, 1 v being full vac and 4V (WOT).As i said before i scope at the ecu so i know ecu is seeing a good signal.
I am trying to understand why you ask about the mechanical fault when i stated the car runs fine so please allow to learn, and any more thoughts are appreaiacted chaps.
On cars running boost the map is internal to the ecu and the 65535 code comes when a small vac pipe spits inside, but obviously my map is on the manifold.
Thanks Lee

Re: audi a2 ,- Poss ecu fault

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 8:39 am, in reply to "Re: audi a2 ,- Poss ecu fault"
Mark Carter

Hi Lee,

I was going down the line that the vacuum is generated by the operation of the valves/pistons against the throttle butterfly.

If the valve timing/overlap is not correct due to a loose belt the vacuum may not be to spec?

I always find it worth checking the general mechanical condition of the beast before I go to deep.

Mark

Modern cars, Its all wizardry and witchcraft

Re: audi a2 ,- Poss ecu fault

Posted by lee hemmings <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3416' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 9:04 am, in reply to "Re: audi a2 ,- Poss ecu fault"
Lee Hemmings

Hi Mark when i scope the map i confirm it with serial data, and vac gauge, which for me is 3 ways of testing the map - and more importantly they all align with each other. I appreaicate thoug that the enviroment can alter the map reading, but as i said in my 1st post the figure was near enough spot on.
I have to say i am still on the thinking ecu fault with this ......

Re: audi a2 ,- Poss ecu fault

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=alankane' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 10:44 am, in reply to "Re: audi a2 ,- Poss ecu fault"
Alan Kane - Administrator

Lee, that type of fault is what I classify as a “perceived airflow issue”. The ecu is telling you as much by logging a code for implausible map. If you think about it, anything that can influence airflow can change the map value and so can cause that code. It doesn’t need to change much for the ecu to be unhappy. The map value you measured may look right but could be slightly out. Ask yourself how the ecu decides what the map value should be.

Re: audi a2 ,- Poss ecu fault

Posted by lee hemmings <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3416' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 12:41 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Lee Hemmings

Hi Alan i agree with the map parameter set in ecu by the maufacturer, therefore being slightly out of spec, the code is given. But my point is this; the spec is good and i would allow for 0.3v tolerance on a pressure sensor. Now if timing etc was incorrect then as mention before we would see out of spec map, so because i am happy with the signal being generated would that not confirmed the map is working within the correct enviroment ?
Also no one as mention the other code yet and the termanology given by the ecu which is unique.
Cheers again Lee

Re: audi a2 ,- Poss ecu fault

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 1:14 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Mark Carter

>>> Hi Mark when i scope the map i confirm it with serial data, and vac gauge, which for me is 3 ways of testing the map <<<

Yes 3 ways of testing the Actual pressure but not comparing it to the mapped spec across the whole rev range.

Mark

Modern cars, Its all wizardry and witchcraft

Re: audi a2 ,- Poss ecu fault

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=alankane' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 2:12 pm, in reply to "audi a2 ,- Poss ecu fault"
Alan Kane - Administrator

<<< so because i am happy with the signal being generated would that not confirmed the map is working within the correct enviroment ? >>>

No, because you could be wrong

As Mark said, it has to be right across the whole range and also under load. How can you judge that is right?

<<< Also no one as mention the other code yet and the termanology given by the ecu which is unique. >>>
I have seen that code set in older diesels but never in a petrol as far as I recall. In the diesels it set for map/boost issues, i.e. perceived airflow issues like your car. In srs modules it is caused by a software issue. An ecu flash could be an idea but I would guess the 2 fault codes are probably related to the one issue.

Re: audi a2 ,- Poss ecu fault

Posted by Darren Bamford <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5465' width='330' height='300' border=0 style='border:none;'> on November 8, 2012, 8:24 pm, in reply to "Re: audi a2 ,- Poss ecu fault"

Hi Lee

65535 in computer talk represent the maximum value for an unsigned 16-bit integer.

65535 is Decimal code, which normally means the ECU responds with all "FFFF" in Hex code and all 111111111111 in Binary code. The ECU has generated a Negative response when asked a question , what ever that question is???

This indicates a internal ROM failure.

Your ECU has a problem FACT.

If a doctor said you had a Major heart condition , and also your hip joint was worn out. would the hospital fix the hip before fixing the heart. I think not.

.

Don't waste anymore time. The ECU fault needs addressing first.

Re: audi a2 ,- Poss ecu fault

Posted by james mccallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 9, 2012, 8:58 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
James McCallum

Hi Lee, have you checked for a software update?
What brought car to you, did light come on and customer brought it in?
Anything else from customer, jump start of vehicle, Has anyone else been fixing it?
Just trying to assertain why the ECU would suddenly generate this code.
HTH Jim

Re: audi a2 ,- Poss ecu fault

Posted by lee hemmings <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3416' width='330' height='300' border=0 style='border:none;'> on November 12, 2012, 1:20 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Lee Hemmings

Thanks Darren, confirming what i thought. My problem is finding someone who can test it.

Re: audi a2 ,- Poss ecu fault

Posted by Andrew West <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5350' width='330' height='300' border=0 style='border:none;'> on November 26, 2012, 10:30 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Andrew West

Hello Lee,
How did you get on with this one? The reason I ask is that I had one in last week, which was intermittently logging injector circuit faults & Map plausibility fault(even after the other garage had replaced the 2 indicated injectors). After quickly checking the timing belt, it was found to be loose & the fuel trims were high at idle (wandering around, sometimes going as low as 3%, but mostly +25%). At cruise & light throttle it was fine.It didn't look too far out on a running compression test, but I haven't had time to check the capture acurately yet. After readjusting the belt it was good at idle & the map reading was also good(as expected), but I didn't get time to test drive it to see if the misfiring reoccured as the cars sales picked it up, as they had their customer due to arrive to collect the car after a reasonably long train journey. I haven't heard anything yet so assume that has been ok so far. I didn't get any Eeprom fault though.
regards, Andrew

Fixed #

Posted by Lee Hemmings on December 28, 2012, 3:29 pm, in reply to "Re: audi a2 ,- Poss ecu fault"
Message modified by board administrator December 31, 2012, 11:05 am

Hi Andrew

Sorry so long since reply been extremely busy, yes I had the ecu fixed and all faults were fixed.

Customer very happy

Lee

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