The battery condition is critical to the operation of the car as many functions - ignition, steering, sliding doors, air conditioning all rely on the battery being up to scratch. The negative is connected to earth. Note also that a faulty alternator can flash up fault messages on the multiscreen.
please see this page for further information
To disconnect the battery:
The BSI needs to go into Sleep mode, during which period nothing in the vehicle should be operating.
- Before disconnecting the battery, turn off all gadgets and lights, open the
driver's window and close all the doors and unplug any diagnostic tool.
The drivers side window has to be kept open for access to the ignition key. - Turn off the ignition and take out the key
- The bonnet should be opened and left up.
- After an interval of 3 minutes the battery can be disconnected
Leave the car alone for at least 30 minutes to allow the electronics to relax. Sometimes it may need to be left for up to 24 hours to reset which may not be good news if you are out and about
To reconnect the battery
- All the doors have to be closed with the ignition key turned off and the key taken out.
- Now without opening the doors, reconnect the battery and wait for at least 30 seconds.
- Turn on the headlights through the driver's window - you may hear a "bong"
- Open the door, may require a reset.
- Get in and start the engine and check everything is working.
- Reset the clock.
WARNING: If you disconnect your battery leave the doors unlocked and the windows open
Do not open the bonnet, lock the doors and disconnect the battery because if you (or some helpful assistant) then closes the bonnet there is no way of opening the doors or tailgate.
The only way out of this situation will involve grovelling under the car as follows:
- All modern cars are negative earth, so using jump leads, connect negative of battery onto a chassis point (or somewhere on the engine)
- The harder bit is to find the live connection on the end of the starter motor - you will need to grovel underneath and find this. As you only need to unlock the doors initially, you won't need heavy wire
- Once into the car, open the bonnet and fit the new battery - wait a while for it to settle and you should be OK. See above for the precautions before rushing to start it!
- Resolve never to do it again