read this and see if it helps.
"Official Battery Replacement Procedure
When replacing the battery on 4.0/4.6 and later model Range Rovers, you should leave one of the doors open (preferably the drivers door) to prevent being locked out. This should prevent the locking system from automatically locking the vehicle and arming the alarm when the battery is being disconnected. Then, disconnect the battery negative lead first, and complete the replacement procedure normally. Afterwards, you need to put the key in the ignition to reset the alarm system and ignition transponder. You also need to key in the radio code to get it working again, and resynch the windows and sunroof. This procedure is described in the owners handbook. On the Mk III Range Rover, you even ave to reset the steering sensor after reconnecting the battery.
In Europe and other markets where passive immobilization is enabled (see alarm system page), the official battery disconnect procedure is to put the ignition key in, turn it to the on-position and back to off. You then have something like 10 seconds to disconnect the battery. If you don't follow this procedure, you will have to use the Emergency Key Access (EKA) method to get the engine started when you reconnect the battery. Kent Clarstroem reports that after many trials, he has found the best solution if you have not used the complete official procedure is to at least leave the key in the ignition. BUT, make sure you leave the drivers door open or you will be locked out! Also noteworthy is that if you do end up having to use the EKA procedure, close the bonnet/hood first. Otherwise, EKA will appear to work but the engine will stay immobilized!!
More details on the problems and pitfalls of the official battery changeover procedure for the 4.0/4.6 are posted on Andy Cunningham's P38 site at
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Improved Unofficial Battery Replacement Procedure
To avoid having to mess with all the details and problems caused by disconnecting the old battery, especially if you catch the problem before power is lost completely, you can maintain power during the changeover by jumpering the cable clamps using wither the new battery or a spare, such as a jump starter pack. Marlon Patton first reported this ingenious procedure as follows:
"My battery was recently dead, and to avoid having to reset the codes I performed an experiment and it worked. I took another old battery and jumper cabled it to the range rover terminal clamps towards the back so I could still get to the terminal bolts. I had the new battery ready and took off the clamps and had a friend hold them by the cables so the jumpers were still attached. Then I lowered in the new battery and attached the terminals and it worked! I didn't have to reset the codes or even worse take it to the dealer and be charged $200 for a battery change."
Kevin Kelly came up with the same idea. When he got in his new Range Rover 4.6HSE at the airport recently he noticed that is cranked a little slower than normal. Picking up a new battery on the way home, he then reviewed the hazards and travail of using the official procedure and decided that it was a lot easier to just use his 12V jumper pack when changing the battery so he would not have to re-set anything or enter the radio code. The photo at right shows the jumper cables attached to the cable terminals of the old battery on Kevin's 4.6 HSE.
Note: In attaching or removing the jumper cables, there is a danger of a spark causing a fire by igniting gases from the old battery. This is why jump starting instructions always tell you to conect the ground last and somewhere away from the battery. You can minimize this risk if you are in a well ventilated area (you can also blow around the battery or spray comressed air if available). If your jumper battery pack has a switch in it as many do -- then you can connect it before switching it on. Otherwise, you might try using a spare jumper cable to connect to the negative battery terminal lead and make the final connection somewhere away from both batteries. As always, be careful and use these procedures at your own risk. "
