Audi Workshop Service and Repair Manuals

The automatic gearbox is controlled electro-hydraulically.

The control unit for the automatic gearbox -J217 is supplied with information from components which influence gear selection, and generates signals to control the relevant solenoid valves in the valve body. The solenoid valves direct the fluid pressure produced by the ATF pump to close the appropriate clutches or brakes in the gearbox.

=> Self-Study Programme 172; Automatic Gearbox, 1995 Model Year

Gearshift programs in gearbox control unit for different driver types and driving situations

These gearshift programs were developed to accommodate the driving style of different driver types. The appropriate gearshift programs are selected automatically for "sporty" or economical drivers to give the best possible performance and refinement combined with optimum fuel economy.

Gearshift program in gearbox control unit according to "motion resistance factor"

The degree of resistance to motion on uphill or downhill gradients or when towing a trailer or driving against a headwind is registered automatically and related to various gearshift maps. The gearshift points are then selected automatically via these maps according to the throttle position and road speed.

Gearbox control unit fault recognition

The term "self-diagnosis" relates to the electronic and electrical components of the control system.

The control unit is equipped with a fault memory so that in the event of an electronic/electrical component failure or an open circuit the fault can be determined quickly.

Faults are detected via electrical signals. If faults occur in the monitored sensors or components, these are stored in the memory together with an indication of the location and the nature of the fault.

The control unit for the automatic gearbox -J217 will diagnose and store particular types of fault under various conditions. After processing the available information, it will distinguish between sporadic faults and static (i.e. continuously present) faults and store them accordingly. Interrogating fault memory =>page 01-35.

When a fault occurs for the first time it is stored as a static fault. If the fault does not occur again after 6 to 24 minutes (or over a distance of 5 to 20 km) it is classified as a sporadic fault (SP).

Faults which are stored as sporadic faults in the fault memory are displayed as such when the fault memory is interrogated with V.A.G 1551 (or V.A.G 1552). In this case, "/SP" appears on the right of the display. If the printer is switched on it will print out "sporadic fault" after the fault is identified.

Faults which are stored in the memory as sporadically occurring faults are automatically erased after 1,000 km (625 miles) or 20 hours.

The self-diagnosis functions are only available with the fault reader V.A.G 1551 (or V.A.G 1552) in operating mode 1 " Rapid data transfer".

For details of functions that can be performed with fault reader V.A.G 1551 (or V.A.G 1552) => List of selectable functions, page 01-32.

Safety functions of gearbox control unit

If critical faults occur when driving, the gearbox will continue to operate in a back-up mode, or "emergency running" program. If the fault occurs with the selector lever in "D", "3" or "2", the emergency running program will engage 3rd gear.

If the fault occurs in "1","P", "N" or "R", the emergency running program will retain whichever gear is engaged.

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 the emergency running mode has been activated when a fault has occurred, the gearbox will remain 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 (see table below).