The replacement Engine Control Module (ECM) needs the Vehicle Identification Number (VIN) to be entered through a hand-held tester by following the appropriate alphanumeric code of 17 digits. The registration procedure requires users to follow input steps first then verify the VIN reading and ultimately write the VIN into the system. You can conduct input operations by pressing the up, down, right, left arrow buttons and 0 to 9 numerical buttons that are part of the tester device. Head to the cursor using the right and left buttons then choose letters through the up and down buttons while numbers come from pressing their associated numbers on the calculator. Users must position the cursor at an incorrect character by using the right or left buttons before selecting the appropriate entry through the up/down buttons or the numerical pad buttons. Proceed by checking that the entered VIN matches the actual VIN of the vehicle before activating the enter button on the tester. The procedure contains a step to read the VIN from the ECM for valid VIN comparison after which the technician completes optional vehicle identification registration and modification steps through the writing process.