Volkswagen Passat 1995 Official Factory Repair Manual page 2851

On Board Diagnostic (OBD), general information
http://ebahn.bentleypublishers.com/vw/servlet/Display?action=Goto&type=repair&id=VW.B4.AT02.01.1
On Board Diagnostic (OBD),
general information
Function
The 096 automatic transmission is controlled
electro-hydraulically. "On Board Diagnostic"
capability refers specifically to the electrical and
electronic controls.
The Transmission Control Module (TCM) -J217-
receives input signals from components that
effect gear selection, and sends output signals to
solenoid valves that control gear selection in the
valve body.
The TCM -J217- is equipped with Diagnostic
Trouble Code (DTC) Memory so that, in the
event of an electrical/electronic component
malfunction or an open circuit, the cause of the
malfunction can be determined quickly.
Malfunctions in the monitored sensors or
components are stored in DTC Memory along
with an indication of the type of malfunction
Malfunctions that occur only occasionally are
defined as "sporadic" malfunctions and are
coded as such.
The Transmission Control Module (TCM) -J217-
analyzes the information and distinguishes
different types of malfunctions. Those that do not
reoccur within 5 to 20 km (3 to 12 miles) or 6 to
24 minutes are stored as sporadic malfunctions.
Page 1 of 19
01-1
12/6/2004