[ECU] Short circuit to ground -> What does it mean?

Discussion in 'Engine' started by ibestriker, May 18, 2006.

  1. ibestriker

    ibestriker New Member

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    [ECU] Short circuit to positive -> What does it mean?

    Hello experts,

    I have sent my ECU to German for repair. When the ECU has been repaired and returned, I asked my Merc Specialist Mechanic to install the ECU.

    But there is an error sounds like this:

    "IFZ: Short circuit to positive"

    What does it mean? Does it mean the ECU is still faulty and not fully repaired? Or is it something else?

    Because of that error, the engine won't start, there is a response of the engine sound though, but the red and green LED on the rear mirror keep blinking. The car doesn't want to start.

    For your info, my car is W202 C-class year 95.

    Hope to get some advices and recommendation.

    Many thanks in advance...your help is highly appreciated.

    PS: I missed my car, almost 2 months not working.. :(
     
    Last edited: May 18, 2006
  2. grober

    grober MB Master

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    IFZ refers to the infra-red remote control . I am guessing that there's a problem with your remote locking/alarm/immobiliser and thats why the red/green light on the mirror is flashing and the car isn't starting. Check your key batteries are OK. Also try disconnecting the battery for ten minutes to see if that resets the system. Remember to take a note of your radio codes.
     
  3. OP
    OP
    ibestriker

    ibestriker New Member

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    The key batteries are ok I guess. But even if the key battery is weak, will it cause that kind of error?

    The battery has been in disconnected mode for about 2 weeks, so I guess the system is already reset.

    What is radio codes? And what does it have to do with the error? Mind to explain?

    Thanks in advance..
     
  4. grober

    grober MB Master

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    Forget the radio !

    Radios can have a security code set. its an antitheft measure . If the radio is stolen- removed from its 12v supply then it wont work until you input the code when its powered up again. This can happen if you disconnect the battery. The code may or may not be set on your radio. NOTHING TO DO WITH YOUR PRESENT FAULT-FAULTS. it sounds as if the car wont start because of the alarm/immobiliser rather than any fault with the ECU so at least that something. Put new batteries in your remote and if you have a spare remote/key try that also.
     
  5. OP
    OP
    ibestriker

    ibestriker New Member

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    Are you saying, it is because of the weak battery in my car key?

    But the door lock can be opened without any problem. And in order to start the engine, it doesn't need any power from my car key, does it?
     
  6. grober

    grober MB Master

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    If you are saying the remote locking / unlocking works via the infra red remote then chances you car key batteries are OK. I still think its the imobiliser/alarm circuits thats the problem but maybe someone on the forum with more specific knowledge of your c200 model can help.
     
  7. pluggers

    pluggers MB Enthusiast

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    There is a good chance that the fob batteries are almost dead.When both red and green LED's flash its does mean they are running low and there is just enough power to send the signal to open the doors but not enough to de activate the imobilizer.
     
  8. OP
    OP
    ibestriker

    ibestriker New Member

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    Thanks grobber and pluggers. So my next step is to change my car key with a new battery? I will try that and see if it works..

    But for your info, the green and red LED don't flash at the same time but alternately. And both the LEDs blink only when the engine is tried to be started (not when I unlock the door lock). Does that mean battery is almost dead?

    PS: But my mechanic said, he tried my ECU into other c200 car, but the same problem occur..the green and red LEDs blink alternately..
     
    Last edited: May 19, 2006
  9. grober

    grober MB Master

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    Last edited: May 19, 2006
  10. Alps

    Alps MB Enthusiast

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    I remember also that a diode in the mirror can go which stops the car starting. Luckily I had my old mirror availible which i plugged in and the car started straight away. Diode was replaced by my independent on the AD mirror, swapped back and its been working fine since.
     

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