A FAW Volkswagen Jetta car with a mileage of over 260 thousand km in 2007. User reflection: the car can't start. After receiving the car: the maintenance personnel tried the car, and found that the car anti-theft warning light flickers. The detection instrument control unit found that there was a hint of failure of the anti-theft control unit. The vehicle is equipped with the third generation of anti-theft devices, and the anti-theft control unit is integrated into the combined instrument, so it can not be replaced alone. Compared with the second generation of anti-theft devices, the third generation of anti-theft devices is characterized by: 1. The burglar control unit can not be changed after writing the password; 2. The engine control unit sends random codes to the burglar control unit, and the latter obtains the control instructions that allow the engine to start after the random code and the password are operated; Unit or engine control unit, the anti-theft password is still the original car code; if the instrument control unit and the engine control unit are replaced at the same time, the anti-theft password is changed into a new code, and the chassis number must be written into the new instrument control unit, and the anti-theft match is made. 2007, the Jetta car's burglar alarm is the same as the burglar car's anti-theft device, so the matching process is the same as bora. Since the vehicle is to replace the meter control unit separately, the password of the original vehicle can be used. From the old instrument control unit data item 17-10-50-XXXX (4 bit cipher), the anti-theft password of the original vehicle is read, and then the new instrument control unit is replaced. The number of passwords and matching keys is written to the 17-11-0XXXX (4 bit password) -10-21-0000X (matching key number) -06 data item of the new instrument control unit. Troubleshooting: recovery of combination instrument, commissioning confirmation and troubleshooting.