Golf Mk3
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Self-diagnosis function
Self-diagnosis function
The automatic gearbox is controlled electro-hydraulically. The term "self-diagnosis" is specifically for the electronic/electric control. The automatic control unit -J217- receives information from components that effect selection of gears and passes the information on to solenoid valves that control the valves in the valve body. The control unit is equipped with a fault memory so that in the event of an electronic/electrical component failure or on open circuit the fault can be determined quickly. Fault are recognized by electrical signals and stored in the fault memory. Safety functions of gearbox control unit The control unit for the automatic gearbox -J217- is equipped with a fault memory. If faults occur in the monitored sensors or components, these are stored in the memory together with an indication of the type of fault. Faults which occur only occasionally are known as sporadic faults and are additionally coded as such. The control unit for the automatic gearbox analyses the information and distinguishes different faults => Fault tables, starting page 01-31 and stores these. If faults do not reoccur within Electrical faults that affect vehicle performance can be determined with the fault reader V.A.G 1551. The possibilities offered by self-diagnosis can only be fully exploited with operating mode 1 "Rapid data transfer" of fault reader V.A.G 1551. Functions which the fault reader V.A.G 1551 can register , List of selectable functions. Safety functions of gearbox control unit If critical faults occur when driving, the gearbox will continue to operate in an emergency running mode. If the fault occurs in "D", "3" or "2", then 3rd gear emergency mode is activated. If the fault occurs in "1","P", "N" or "R" then the emergency running mode for that stage is activated. If the engine is started again in the emergency running mode and the fault occurs when selector lever is in position "D", "3" or "2" then 3rd gear is activated hydraulically, until the fault is rectified. If faults exist which result in emergency running, the gearbox remains in the emergency running mode until the ignition is switched off. Faults which may lead to emergency running: Open circuit in wiring, short-circuit, electrical or hydraulic components defective. Gearbox control unit fault recognition If a fault exists for a certain time, it is stored as a static fault. If the fault no longer exists for a certain time or distance, it is considered a sporadic fault. Faults which are stored in the memory as sporadically occurring faults, will be displayed as "sporadic faults" when retrieved by fault reader V.A.G 1551. "SP" appears on the right of the display in such cases. If the printer is switched on, "sporadic faults" are printed out after the fault is addressed. Faults which are stored in the memory as sporadically occurring faults are automatically erased after 1,000 km (625 miles) or 20 hours. |