You will need to have it programmed by a shop or dealer with ob2d programming software (Launch X431 we recommend). Your VIN# must be added to it along with linking your car key immobilizer or it will not work! This would be the case on any ECM you buy, used or new. The immobilizer and VIN# have to be added to the ECM or car will run for seconds and turn off. You do not need new keys etc - this is not true. Up for sale is a factory new OEM ECM/PCM - not a mile on it. Only fits what is listed below. No miles on it! Fits: 2003 Altima 2.5L - Manual Transmission - with Cruise Control The number on your old one must match: 23710-9J010 23710-9J011 23710-9J012 23710-9J013 We will gladly ship worldwide. Please contact us with any questions!! Thank you!!! INTERNATIONAL BUYERS! PLEASE NOTE! Buyers of items shipped outside the USA are responsible for customs fees/taxes/duties and may encounter delays due to customs inspections. PLEASE be aware of this!