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Hi, I need to disconnect battery to reset ecu.

my question is which terminal do you disconnect first?

+Ve or -Ve first?

would I need to disconnect both in order for the whole car to open circuit?

any safety precautions when do so?

Car battery provide 12V power right? instead of 240V at home! so if any thing goes wrong, i wont become a :ghost: right!!! :headspin:

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lol.. no you won't go toasty..

Always best to disconnect the positive first and leave the ground to provide an earth. Soon as you disconnect the positive the power will be disconnected.

When putting it back connect the ground first, then positive.

It may make some sparks when you connect back the positive nerminal, but its generally ok.

yeah always take negative off first, that way there is no ground to get the power out...

if you undo the positive, there is a chance of grounding the spanner from the positive terminal to the body of the car which will create a circuit and end up going back to the negative side of the battery... bad

if you disconnect the negative side, then you can't create a circuit...

if you just want to disconenct the battery, just one terminal is enough, no need to take both off... unless you are removing it or charging it etc...

I have just finished the reset the ecu and took it for a drive! BEAUTIFUL, I have yet to take it for a long drive. Tommorrow, if all goes good, I will make a new thread about it. Any thanks all... I have removed both terminals! man, the job took 1 hour plus cause my amp is fixed to the back wall! have to removed that to access the battery!

when you disconnect the one side press the brake pedal a few times to discharge any power. the ecu can keep the settings in memory and the car will have enough power for about 12 hours to survive without the negative connected. the old school way was to remove the negative and leave it overnight but the quick way is to disconenct it and press the brake pedel, this will use any left over power in the system

  • 6 years later...

when you disconnect the one side press the brake pedal a few times to discharge any power. the ecu can keep the settings in memory and the car will have enough power for about 12 hours to survive without the negative connected. the old school way was to remove the negative and leave it overnight but the quick way is to disconenct it and press the brake pedel, this will use any left over power in the system

You'd need to turn your ignition to on before pressing the brake pedal though because brake lights don't come on with no key in the ignition I don't think?

You'd need to turn your ignition to on before pressing the brake pedal though because brake lights don't come on with no key in the ignition I don't think?

You don't need to do this, + they probably knew this back in 2004 too nyaanyaa.gif

You don't need to do this, + they probably knew this back in 2004 too nyaanyaa.gif

HAHA! i really really need to start reading how old a thread is that i'm replying to. done this a few times now just using search. lol

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