Battery Remove / ECU Problem?
 

Hi,
I need to replace my reverse light switch on my 03 Focus RS, although the battery has to be disconnected and removed to gain access.
Will this erase / reset the ecu? Im especially worried since the car has had a remap! :(

it will reset the ecu to but shoudnt erase the map on it mate.
when you start it back up put all electrics on,lights aircon etc on and take it for a drive.

fire a post on rsoc,they guys will know for sure

The ONLY thing that will get erased will be the KAM (Basically the fine tuning the ECU has adapted to) as soon as start it up and drive around it will re learn this information.

It's important to know/have a note of your radio code though as this will need re entering.

All MAPS on ECU are non volatile.

Martin

As above, will not cause an issue, you will only loose the KAM, which will be re-learnt in a few miles anyway. Only thing you will loose is the radio code! Not sure why to put all electrics on first though?

just going by what ive read on the focus section on the rsoc,guys on there know the frs inside out so sure theres a reason for it

The only logical explanation I can think of would be that it puts a large load on the alternator, so the ECU adjusts fueling to suit, yet when you turn them all off, then you have the extra fueling thus more power. However the KAM would readjust within a few miles so seems a bit pointless to me!

A bit like a load of biffs on the STOC always pull the fuse for the KAM after they have been driving slowly so it resets it. Yet it adjusts itself within a few miles according to your driving style so seems a bit odd as to why you would bother!

No need what so ever as you say, the ECU is 'adaptive' so that it can adapt to the driving conditions!

Martin