Volkswagen Passat 1995 Official Factory Repair Manual page 1508

General information for On Board Diagnostic (OBD)
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General information for On
Board Diagnostic (OBD)
Characteristics of On Board
Diagnostic (OBD)
Engine Control Modules (ECM) and
Transmission Control Module (TCM) are
equipped with a DTC memory.
Malfunction recognition
If malfunctions occur at the relevant emission
systems or components, they are stored in
DTC memory with a description of the
malfunction type.
Control modules differentiate between
different DTCs after evaluating the information
DTC tables, Page ST-56
The stored malfunctions can be checked with
a standard diagnostic tester
Diagnostic mode 3: Check DTC memory.
When harness connectors are disconnected
from the Engine Control Module (ECM) or
Transmission Control Module (TCM), or the
battery is disconnected, all adaptation values
in the control modules are erased. DTC
memory content will remain intact however. If
the engine is started after this, rough, uneven
idle can result. In this case, the readiness
code must be generated again
52 .
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ST-1
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Page ST-22 ,
Page ST-
6/12/2004