Battery Change

[p.masterman]

I want to change the battery in my 75 V6. In order to retain the ECU/radio codes is it safe to connect an auxiliary 12v battery to the cigar lighter? I shall of course be careful to observe correct polarity. Thank you.

[Moonstone]

If your radio is a Symphony, the codes may not be enabled. It seems many dealers didn't bother setting this on delivery (although you can enable them yourself, I believe).

[p.masterman]

Thank you Moonstone - no it is not Symphony, however, it is more the ECU that I am worried about.

[Christopher]

There should be no problem with ECU codes at all on removing the battery, so you should be OK there.

[JohnDotCom]

The only one you should really worry about is the HI Line Sat Nav system and ensure that it is all shut down properly, if not it wont work and you will need a new Sat Nav Computer.
Open your Doors and Bonnet and anything else you may have to open on car, then watch the light on Sat Nav computer until it goes off (red Light gone) now it is safe to change battery or even remove sat nav components. If you open any door/boot/tailgate before shutdown you have to wait again as any eletrical operation restarts the sat nav system!