on some of the vehicles you will come across, an eight pin eeprom chip will be used to store the vehicle data. these chips hold vital information from important to read and save the original information from the eeprom before programming, from minor faults, to major faults involving the vehicle not starting and having to be taken to the main dealer. this is why it is very the vehicle such as ignition and immobiliser codes. loss of this information could result in anything this way if any errors do occur you can always return to the point you started..syi