You will need to take out the battery and air filter box. There are two numbers, one stamped the aluminum body and one on the module. Your best option would be to get a second hand one if you can match the numbers, something I couldn't manage! I eventually got a new one direct from bosch for £600 (it took 8 weeks as the had to make one specially) which solved the problem with the abs but the water ingress had damaged the cables and I had to have the cables cut and partially replaced otherwise I would have needed a new wiring loom! Bosch were reluctant to supply one as it is a common fault on the Nissan Micra due to the position of the unit and ingress of water. I wouldn't bother sending into a ecu testing company as i sent mine at considerable cost and I ended up with the car hunting for revs which was never solved. Once you have installed it you will need to take it to someone with bosch equipment to reset the system and settings, again more money. Have you considered trading it in? It maybe cheaper. I tried the scrap part web sites on the internet, all said they had the parts but when I sent the numbers they could not match them up. If you have a full nissan service history they will contribute towards the part and labour? Good luck.