Inquiring about car electronics.

Discussion in 'Automotive Electronics' started by R!f@@, Jun 14, 2017.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Hey Guys.
    I am looking for anything and everything regarding car related problem I am facing.
    Story is long and to dumb it down, the car is not working.

    It's an Audi A1.
    I need help and advice if any one has any knowledge about the BCM, door lock and key programing.
    I can explain the situation if needs to be.
    For now, if any one got any experience in this field let me know, so I can continue.
    Thanks.

    PS. This is not the only one. Got a BMW too.
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Don't know it either car has or uses them, but one thing that stumped me once was "fusible links". They are a short piece of wire, usually orange in color, that is one gauge smaller than the wire they are supplying. The orange insulation is to make them stand out bur they are usually hidden under the battery tray. The insulation is made of a teflon material so they don't burn and start a fire, but the conductor melts like a fuse. The last place I worked made the fusible link wire on a special line just for that product, due to the way the teflon was applied. They are crimped to the standard wire and are only around 1 1/2 or 2 inches long.
     
  3. debe

    AAC Fanatic!

    Sep 21, 2010
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    Car is not working is a very broad statement, could cover any thing. If its a no crank situation there may be dry joints on the BCM module particularly any relays.
     
  4. bwilliams60

    Well-Known Member

    Nov 18, 2012
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    R! F@@, you have my interest? What is your issue?

    Shortbus, just a quick FYI for future reference. A fusible link is generally a piece of special wire which acts just like a fuse when too much amperage passes through it. The insulation is high temperature fire resistant so that all heat and flame is contained in the casing. Generally they are on average 6" long but can run up to 9" length maximum. The size is 4 American wire gauges smaller than the circuit it protects so a 6 gauge wire would be protected by a 10 gauge fusible link. These have since been replaced mostly by Maxi-fuses on newer vehicle.
     
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  5. wayneh

    Expert

    Sep 9, 2010
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    You need to look for forums as specific to your vehicle as possible. It's been rare for me to have a problem with my van that someone else has not already diagnosed and solved. There are even videos addressing some of the more common problems.

    Finding the service manual is also useful. It should describe how the various components interact and give procedures for resets, diagnostic work and so on. You may have a security system problem but it could be as simple as a broken wire under the hood.

    An OBD reader is cheap, nice to have, and might help. You have to be careful to get one that works with your car.
     
  6. #12

    Expert

    Nov 30, 2010
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    I go to a Ford website to work on my car. This site has been non-automotive for so long that we don't have a reasonable accumulation of automotive experts. That's what car sites are for. That's where the car people play.

    And don't forget the manufacturers resources. My keyfob did not work. All I had to do was follow the instructions to teach the car to listen to the keyfob I had in my hand.
     
  7. R!f@@

    Thread Starter AAC Fanatic!

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    Thanks all.
    I will get back to you with the full story.
    I got a OBD but I need to see if it has the Audi file.
    I dunno any car forums but if anybody here got any idea, I'd rather not register any where else.
     
  8. bwilliams60

    Well-Known Member

    Nov 18, 2012
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    Can you describe the problem you are having? I may be able to help if I know what is going on. Or not.
     
  9. R!f@@

    Thread Starter AAC Fanatic!

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    @bwilliams60 Thanks
    I will get some time off later tonight and I'll explain everything from square one.
     
  10. shortbus

    AAC Fanatic!

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    The special insulation in GM/Packard fusible links was as stated, a teflon/PTFE insulation the internal wire was just standard drawn copper strand. Was there where it was being made, saw the cells of raw teflon pellets and saw the copper drawn from raw copper bar.

    Was remembering the gauge difference from memory.

    The Pontiac I worked on only had ~2" long links. But the ones sold in the parts store are ~6", you cut to fit.

    Agree with the Maxi fuse.
     
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  11. IMP002017

    Member

    Jan 28, 2017
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    Sadly one mistake that most make is that they disconnect the battery while trying to solve problems before running a OBD test. Also if the car has dead battery it can clear the history of the BCM.

    First thing is needed to check that your car has the 3 things that make cars run. Air, Fuel and Spark. I know there are issues at times where there is spark or thought there is but is after a condition of when spark should be there, Could be after switch is turned off at the end of a Crank.

    So then you need to find out if your car has spark though crank, Fuel at the rail under the right pressure and that your computer is not sending the wrong info because of a Bad MAF or Map sensor. for the air.

    Need to check all fuses, test all relays for fuel pump and that there isn't any security lights on the dash for cars that have chip in key or other type of lock out. Most times if there is a key issue the BCM will not send the Relay for the fuel to run so you won't have gas. YOu can try on cars with that option by using a starting fluid however that is risky and can harm cars today more then help so doing so at your own risk.

    There are some cars that also or only turn off the Ign portion of the starting so that would have the BCM not offer the command for spark.

    MOre info about what lights are on the dash would also be helpful with year, make and model of car*s*
     
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  12. wayneh

    Expert

    Sep 9, 2010
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    Yeah, even an expert needs more info than that! There's a no-crank-condition, where nothing happens when you turn the key, there's the crank-but-no-start condition, there's the starts-but-dies condition, runs rough, won't shift, and on and on. These are all very different situations with different diagnostic trees to follow.

    A precise description of the problem is the first step to a repair.
     
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  13. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    And...we can't listen to it.
     
  14. bwilliams60

    Well-Known Member

    Nov 18, 2012
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    Did I miss something? It would seem we have solutions for a question that has not been asked yet? I think we need to know what the exact issue is and then logically approach it. Checking this and that and every other thing is wasting time. Automotive electrical does actually have a procedure to follow although the above approach is more common. 90% of the diagnosis is in the description of the problem and understanding the system. That is why my industry has way too many parts replacers in it now. They can't think their way through the problem.
     
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  15. bertus

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  16. R!f@@

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    Sorry Guys. ! :(
    Took some time to get the info I needed to share.
    Recently I was told to me it doesn't work, I did not know what part. I did attend to it before but few months went by after that and recently they came back and said still it does not work.

    Long Story :
    I am not sure when the problem started.
    They said it occurred when the battery was replaced. Who replaced it I dunno know. But My assumption is they connected it in reverse.
    I checked. Initial symptoms were,
    1. Door lock works.
    2. Engine can be started.
    3. Audio system was dead.
    4. Head light lights p and 4 signals starts to flash as soon as the Engine is started and cannot be turned off. All light goes off when Engine is shut off.

    The info I got from the guy attempting to repair
    Some one came and diagnosed it ( call him tech 1 ) he said BCM was the problem . Took money for a new one and vanished. Still not answering the phone.

    That is when I came in and checked. I started with the audio system. It is not powering up. found a fuse dead, before replacing checked the audio unit, and found the reverse protection diode shorted. fixed it and audio is working and A/C is working. Same flashing lights.

    I do not have a diagnose so I cannot trace any error codes. All he had was an OBD, with it I cannot find any thing.

    With the old BCM only issue was head light and signal light.

    Then few months later ( now )
    He came back asking for help. He said another guy came ( tech 2 ) and diagnosed said BCM. took the money and bought a new one ( used one, I believe )
    plugged it in. Nothing worked. No engine start and locking doe not work. So he dismantled the driver side door lock. Cannot put it back as it was. So he vanished. :mad: So now I need to see if I can put the lock back together ( yet to be attended ). :oops:

    Tech 1 took more than $5K. Still AWOL.
    Tech 2 took $1.6K for diagnosing
    Tech 2 bought $2K ( not with his money ) worth of stuff, BCM, dash board meters and A/C control switched which so far are useless. He too is AWOL.

    The new BCM also shows a steering symbol on the dash board.

    Since now the lock is dismantled the owner has to buy a BCM, lock, and a key, which costs around 800 euro.

    I believe this can be solved with the old BCM and if I can put the lock back together.

    So what do you think. :)

    PS. I am the only one who actually did something and I haven't got a penny yet. :(
     
    Last edited: Jun 17, 2017
  17. bwilliams60

    Well-Known Member

    Nov 18, 2012
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    Where do you live? I think I will move there if you are getting $5K for a used BCM or even a new one.
    I would start first by putting everything back the way it was originally and tell the guy nobody works on it from now on other than you until it is fixed. If he wants to get other people involved, walk away...........no run.
    Once it is back to original, you will want to see if it can communicate on the CAN Bus by spitting out codes or perhaps put an oscilloscope on it and see if there is any activity. Some modules will take higher voltage or reverse voltage without damage. Disregard everything else that is happening in the car for now. We need the BCM to work. If the BCM is in fact damaged, we need to see if we can get the program off of it so we can copy it onto the new BCM. If not, many weird things will happen. I am not sure of the year of the car so that is why I say it needs to be programmed. If it is old, swapping BCM's should get communications going. If you do not have a code reader, buy one. They are under $100 for a decent one.
    Let's start there and do this logically. :)
    It is possible that it has a corrupted program and neds to be reflashed by the dealer. If the guy doesn't want to spend money, he is driving the wrong car.
     
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  18. IMP002017

    Member

    Jan 28, 2017
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    Sounds like a handful for sure. Sadly hard to tell what the real issue is without being there. I know there are some issues with things that are Aftermarket and it almost sounds like that is what all the flashing is when you connect up the battery.

    Most alarm systems has a connect at last state feature that if the alarm is going off when the battery is disconnected that it will return with alarm still going. IF that is the reason for the flashing lights that could also stop the car from Starting as well.

    So it sounds like this isn't your car and I am not sure what is known about the car. Hard to tell without being in front of it. What I would do is look for evidence that there was or is an alarm installed. There could be a Siren under the hood that someone disconnected so they don't have to hear it going off while working on the car. First thing *I* would do while light going off and found a disconnected siren is connect it and see if it is going off. (Help to confirm)

    Not all systems have a Siren so it could be that it was connected to the horn and that was disconnected. So then I would look under the dash of the car, In the glove box or any type of box for storage for a push type button most times would be red. Or some type of small toggle switch again could be red tipped. If push button one is found. Turn on key to car and press and hold the button. There also could be a LED on the dash or console most times red but could be any color for state of alarm. Once button is found and system is in Valet the Led will go to solid.

    About the door lock. That can be hard at times because they are not all the same type or hooked up the same. Most cases a view from the dealer of what is where can be enough to get something back together. that is where I would start if I didn't know the system already.

    year of car make and model would be helpful as well.
     
  19. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Thanks you both. Really.:)
    I phoned the guy in charge to get the details of the car, he will meet me soon and I will post the details ASAP.

    @bwilliams60
    The guy in charge has spent a lot on wannabe's, So I believe he can spent a few more since I am involved. At least I am the one who actually did something :D
    I have a scope. I can scope it but I still dunno where. First time attempting such a repair. :oops:
    I will put the old BCM back and check it and get the problems before continuing.
    Before that please don't pour everything on me at once, I like a step by step route. :(
    I understand the part to not to involve any one else during the repair. It is good as done
    @IMP002017
    I dunno about any siren and I did not hear anything before but I will check it

    I believe the battery flat lined, since it is not the only car he has. Because of the Audi, he already bought a 2016 BMW. That baby is beautiful. Still not registered yet.
    The battery died and may it was that way for a period of time. Just assumptions.

    PS. Do I need to try to fix the lock ?
    Or get a new one ?
     
  20. R!f@@

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    There was a mistake in my post regarding steering symbol with BCM. It is corrected. :oops:
    Sorry :(
     
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