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Thread: Can not ready

  1. #11
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    Ok guess I just have to hope that the led bulbs flickering when I turn the key on doesn't kill them too fast.😆 Thanks for your help I appreciate it.

  2. #12
    Verified VCDS User PetrolDave's Avatar
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    Quote Originally Posted by Zdouble View Post
    Ok guess I just have to hope that the led bulbs flickering when I turn the key on doesn't kill them too fast. Thanks for your help I appreciate it.
    Have you fitted resistors in parallel with the LEDs?

    BTW I have owned a B6 A4 TDI, 2 different B6 S4s and a B7 RS4 - the modules in them were definitely "old school" and low tech compared to current vehicles - not surprising when you remember that the B6 was designed in the previous millennium and the B7 was little more than a mid-life upgrade.

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  4. #13
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    Ya some have built in resistors, others I installed so I have no bulb out warning. They just flicker when you turn the key on which is what I wanted to stop by turning off cold diagnostics.

  5. #14
    Verified VCDS User PetrolDave's Avatar
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    Quote Originally Posted by Zdouble View Post
    Ya some have built in resistors, others I installed so I have no bulb out warning. They just flicker when you turn the key on which is what I wanted to stop by turning off cold diagnostics.
    Sounds like the resistors have a fractionally too high resistance which isn't cleanly "fooling" the cold diagnostics. Remember the resistors will get very hot when the bulbs are on, so mount them somewhere appropriate.

  6. #15
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    No I don't think you can stop the flickering no matter which ohm resistors you use it happens when the computer sends the signal to test to make sure if each bulb is not burned out.

  7. #16
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    Let me rephrase it it's actually a strobe effect not flickering. The ecu sends out a few pulses to check the bulbs, it looks cool but Apparently it kills the LEDs quicker.

  8. #17
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    Could still do with seeing an autoscan really.

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  10. #18
    Verified VCDS User PetrolDave's Avatar
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    Quote Originally Posted by Zdouble View Post
    Let me rephrase it it's actually a strobe effect not flickering. The ecu sends out a few pulses to check the bulbs, it looks cool but Apparently it kills the LEDs quicker.
    The pulses IIRC are at reduced voltage (so incandescent bulbs don't generate anything visible).

    As an electronics engineer of over 40 years I fail to understand why these pulses would "kill" LEDs

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  12. #19
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    If they don't than thats great! Thanks

  13. #20
    Benevolent Dictator Uwe's Avatar
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    Quote Originally Posted by PetrolDave View Post
    As an electronics engineer of over 40 years I fail to understand why these pulses would "kill" LEDs
    Agreed. The brightness of LEDs has traditionally been modulated using PWM techniques, and I've never heard of that affecting them in a negative way.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

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