Car ECU (Engine Control Unit)

Discussion in 'The Guru's Pub' started by kanej2007, Sep 25, 2014.

  1. Im2bad

    Im2bad Guest

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    I'd change the ECU, if you can get it for that 30 pounds. It is entirely possible the earlier TPS, which was changed, was OK, it was just the ECU thinking it was broken due to some problem with the unit's internal components. Dry joints(I'm not sure if this is the right term in English) do happen sometime, which work okay most of the time but can randomly act out.

    I've heard that Siemens ECUs from those years aren't very reliable, but I wouldn't put much stock to it. Although, I keep getting a check engine light on my Volvo but it doesn't seem to have any effect on anything.
     
  2. IcE

    IcE Don Snow

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    Lol, what an idiot. He could have easily checked it and found the code in the history...
     
  3. kanej2007

    kanej2007 Guest

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    True, I did mention that to him with which he responded by saying ''that's rubbish, we cannot diagnose an error code without it being displayed. ''

    I knew he was wrong but didn't bother arguing and simply left...

    Till now the code comes on at times when starting the car or simply after a 15 or 30 minute drive...

    I'll have some free time later on this week and I will get it checked by a different place and hopefully diagnose the issue and change the faulty part if necessary.
     
  4. TaskMaster

    TaskMaster Ancient Guru

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    Christ man. You've been so unlucky with your cars.
     

  5. kanej2007

    kanej2007 Guest

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    Yeah, I get the most annoying and complicated problems ever.

    What I liked about the older cars were the fact there were no sensors, everything was analog.

    All the later cars are digital, full of sensors and they can go wrong at anytime...

    Several years ago, my old Mercedes SL500 R129 never gave me any warning lights apart from low oil, brake pads, etc...

    The issue I have seems to be common in Volkswagen, Seat and of course Audi, being the A3/A4 range which is me. :(

    Definitely this weekend over the eid I'll get an update as I plan to take next week off.

    Once the $hitty EPC light is displayed I'm calling the garage, making sure the ARBAB is there, get it scanned and fixed while I wait!
     
  6. Constant

    Constant Guest

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    Group Vag electronics are fast accurate and have great potential when tuned.

    But just like all complex mechanisms , there are too many variables that could go wrong.
     
  7. kanej2007

    kanej2007 Guest

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    Yeah, I've heard od Group Vag electronics. I'll check what computer they use once the car has been scanned.

    And there are indeed many variables that could be wrong thus triggering the EPC warning light...
     
  8. AsiJu

    AsiJu Ancient Guru

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    ^ yours should be VAG (Volkswagen Group) as it is as you have an Audi ;)

    Unless I'm very much mistaken.

    PS: based on what you wrote before, yeah check and double-check the mechanic you use.

    There's a memory on the OBD for error codes so old codes can for sure be diagnosed, unless the memory's been erased (which too can only be done at a shop "officially").

    PS2: if the EPC light keeps flicking on and off, then there's probably just a bad contact somewhere in the circuit of the ECU.

    Still, finding the bad contact is more or less a work of a mechanic, but chances are your ECU needs neither reprogramming nor replacement.

    People with more experience with Audis could probably even suggest you some remedies / things to check.

    Try googling "Audi A3 EPC light" or similar, you'll probably find some info that way.
     
    Last edited: Sep 29, 2014
  9. IcE

    IcE Don Snow

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    You should have kept the SL500. Those things are bulletproof, apart from having expensive parts. Plus they look way cooler, especially the generation you had. :nerd:

    But also have your charging system checked. Weird electrical problems can be caused by a charging system on the fritz. Check battery AND alternator as well as the entire circuit for proper voltage and amperage.
     
  10. kanej2007

    kanej2007 Guest

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    Yes, the error code should automatically be stored in the ecu when triggered.

    The code was reset several days ago when I went to the garage.

    Naturally, the EPC light came straight back on. It's on most of the time, even when starting the car.

    Otherwise within minutes it usually appears and stays on.

    I will be visiting the garage on Thursday and will hopefully have an update on the situation.

    Thanks for the info.

    Yes, I do indeed miss my SL500. My father himself told me several times not to sell it and to keep it. The car was strong, reliable and great to drive.

    The only issue it was heavy on gas. Naturally a 5 litre V8 would be, not a surprise...

    Honestly, parts for my SL500 were not too expensive, you just had to know where to go.

    Near where I live, there are many shops who stock parts for Mercedes as well as other German cars. Prices were good because of high competition.

    I will get the garage to check the charging system, battery, alternator as well as the circuit for correct voltage and amperage as you advised.

    Thank you so much for the advice ice.

    I'll let you know the outcome on Thursday or so.
     

  11. AsiJu

    AsiJu Ancient Guru

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    ^ hope you get it sorted!

    You really have had your share of car trouble...

    Get a Japanese car next time, maybe ;)
     
  12. AaronT

    AaronT Guest

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    Hi guys.

    Both are partly true. Some diagnostic trouble codes (DTCs) can stay logged for many key cycles and some can clear after a couple of key cycles. This depends on the ECU and the manufacturers software.

    I would also get the connections to your accel pedal and throttle body checked for tension, cleanliness and perhaps some nyogel (conductive grease) to ensure a good connection.

    Just a couple of thoughts from a current Ford service manager which varied make and model experience.
     
  13. kanej2007

    kanej2007 Guest

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    Thanks mate, your not the first one to mention getting a Japanese car. I agree they are less likely to suffer from electronic/sensor issues. German cars, especially newer ones are very sensitive. Any little issue and you get warning lights. :)

    Thanks for the advice. I have a gut feeling the issue is throttle related, probably the accelerator pedal since the throttle position sensor was recently changed.

    I'm living in a hot and dusty climate (Dubai) and as you mentioned there could very well be dirt/dust surrounding the connections thus causing issues.
     
  14. thatguy91

    thatguy91 Guest

    Is there a warning label on it?

    WARNING: Group vag electronics cause vibration
    (hint: I'm being rude!)
     
  15. TekkMarine

    TekkMarine Maha Guru

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    I have the same problem!... same car too I think. I hope that can be fixed somehow. ^^
     
    Last edited: Oct 1, 2014

  16. Constant

    Constant Guest

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    can be fixed easily :

    next time buy a Lexus or smth :p

    thatguy91 , i had an AUDI A4 1.8t Sedan aWD

    Used it as my daily car

    I was returning home on a rainy night , parked it outside on the street cause my garage was full.

    Next morning i woke up just to find out that the car was filled with water as all 4 windows were opened all the way down during the night...

    When i took it to the dealership they came up with the conclusion that "THIS WAS SUPPOSED TO HAPPEN" so as to save me in case i drove into a lake or sea....and it was simply an over-sensitive water sensor....that made my car ecu into thinking it was thrown into the sea...

    So much for the complex electronics
     
  17. kanej2007

    kanej2007 Guest

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    Just a quick update. The car was scanned this morning and these were the error messages:

    1 - Throttle Position Actuator - Implausible signal
    2 - MAF (Mass Airflow Sensor) - Implausible signal

    The car is a 2003 Audi A3 1.6. This evening I should get an update. My car is currently being repaired in the garage. I hope the issue is solved.
     
  18. AsiJu

    AsiJu Ancient Guru

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    ^ was the ECU reprogrammed already or are those error codes "as is"?

    The Air Flow Sensor, if I recall, was already given as fault previously (in your previous thread) and I suggested you replace it or try cleaning it like I described.

    So chances are this is the exact same thing just happening again.

    Replace or clean the Air Flow sensor (try cleaning it first), it will surely help at least.

    Injection (=modern) engines simply do not function without a properly working MAF.

    CRC has a liquid for cleaning the sensor called "Turbo Mass Airflow Sensor Cleaner" or similar. You will surely find a STS equivalent or other where you reside.

    ADD: post a screenshot of your engine, I'm pretty sure I can point out the MAF to you. The cleaning (and replacement) are jobs you can easily do yourself too.

    EDIT: well, I suppose you needn't do any of this if the shop gets your car fixed ;)
     
    Last edited: Oct 2, 2014
  19. kanej2007

    kanej2007 Guest

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    ^ Thanks guys for the reply. Sorry I haven't posted any updates over the last few days.

    Thing is I had no news, only the same issue is still continuing to persist!

    The car was collected from the garage thursday evening. No EPC light was displayed that entire evening.

    Next day, afternoon, the EPC light starts coming on again, not going off. Grrr.

    I just paid around £200 for parts and labour. MAF sensor was apparently changed, air vacuum and throttle position sensor.

    Next day light is on again. I am pissed having this issue ongoing since early 2012, only getting worse.

    I've spend hundreds of pounds on parts, labour and the EPC light remains on at all times...

    After referring to other forums, other owners have had similar issues and have spent months and months in garages changing half the engine and the problem remains. :(

    It's complicated, so much time and money has been wasted for a problem not yet solved.

    The garage is now shut until monday (eid holiday, muslim holiday) .

    I will return monday morning and DEMAND the garage spent their time and money fixing my car.

    Why pay £200 for a problem that has not been solved and the very next day (under 24 hours) returned?

    How would you guys feel spending money, times and months of constant trips to garages for the very same issue that's yet to be solved?

    Makes me feel like driving the car at full speed into a brick wall.

    Next week I'll hope for some news as to why the issue remains, cause and if possible a solution.
     
  20. kanej2007

    kanej2007 Guest

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    From what I've been told, the ECU has indeed been regrogrammed.

    The MAF sensor, Throttle body and throttle position sensor have all been changed. I will ask that they are tested and cleaned.

    Here is a photo of my engine, all red circled parts are sensors and such which were changed:

    [​IMG]
     

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