How do I please my VCDS cable?

   #1  

DV52

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I know that it is unhealthy (and more than a little weird) to have a “connection” with an inanimate object like a VCDS cable but I don’t mind admitting that I have (on a few occasions) uttered the odd expletive in the said cable’s direction when it's not behaving correctly. Mercifully though, I have never heard the cable respond (that’s a good thing as I understand!).

My love/hate relation with my cable notwithstanding, I’m a firm believer in the ledger-book principle, That principle being, if I look after my equipment, then it will look after me (particularly when the piece-of-kit in question is expensive). So here’s my question; Is there a right and/or a wrong sequence to hookup the cable to the car/laptop and then to disconnect the cable when finished?

I’m aware of the purpose of the LED thingy on the dongle end and it’s always reassuring when it changes colour to tell me that all is OK at the OBD socket end (see the cable does speak - in a fashion). Incidentally, has RT considered duplicating the LED on the apposite side because on a few cars, the LED points down towards the car-floor when the OBD socket is upside down?

I’m interested in learning about the connect/disconnect sequence in general if-any, but here are a few questions as a thought prompt for would-be responders.

1. Should the OBD end be connected first?
2. Should the Car’s ignition be off when connecting the cable- does this matter at all?
3. What is the boot-up sequence for the cable - is there a boot-up sequence?
4. Does it matter if the car’s ignition is on when the cable is disconnected?
5. Are there any hardware/software protocols at all that a cable owner needs to be aware-of when hooking-up/disconnecting the cable?
 
   #2  

Uwe

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1. Doesn't matter
2. Doesn't matter
3. Not really.
4. Doesn't matter.
5. Don't using any power sources that might cause a ground loop. Cheap 12V laptop power supplies can be a problem. A cheap battery charger connected to the mains and the car at the same time your computer is connected to the mains can also be a problem. Lastly, don't let your computer's battery die while communicating.

-Uwe-
 
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jakematic

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Lastly, don't let your computer's battery die while communicating.

Nor the one in the vehicle.
If a procedure says to attach a charger, do it :)

Longer sessions I always just start the vehicle unless it goes against the instructions.
 
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Sebastian

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Technically any diagnostic session exceeding 15 minutes should be performed with a proper (at least 35A) battery charger attached to car. Some vehicles and procedures may require a charger up to 70A! Also make sure to connect the charger properly, models with battery management and/or start-stop-system will require the charger to be connected in a way that the battery management does see the charging current before it goes to the battery. If you connect it straight to the battery in those case, the shut-off stages may be engaged falsely possibly resulting in troubles while running diagnostics.
 
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Uwe

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I think that 15 minutes thing is an awfully broad rule-of-thumb. Depending on the condition of the battery and the type of car (and its electrical consumption) you might not get 15 minutes. When in doubt, connect a battery charger -- or at least run the engine. But this really for the car, not the cable. The cable will be fine down to voltages well below those at which the car begins to lose brain function. ;)

-Uwe-
 
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