Carina E immobiliser probs after battery change

Assuming you have a factory theft deterrent system, try unlocking the door with the key instead of with the fob, then try starting. You may have to re-program the theft deterrent system.

It's a factory fitted job. We've been using the key since we've had the car. I only use the keyfob at times like this. It worked the other day just after I charged the battery, but seems tired of life since I've changed it.

So I'm guessing it needs to be reprogrammed? Is there anything online about how to do this? Can it be done by the car owner or is it a Toyota job?

Thanks.

The security system probably needs to be reprogrammed. Toyota's has an online factory repair manual available for U.S. models for U.S. $10/day, they may have a similar service for your location.