Volkswagen Passat 1995 Official Factory Repair Manual page 722

On Board Diagnostic
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On Board Diagnostic
Function
The Motronic Engine Control Module (ECM)
J220 is equipped with Diagnostic Trouble
Code (DTC) memory.
Malfunctions in monitored sensors or
components are stored in DTC memory along
with an indication of the type of malfunction.
Check DTC memory and display stored
Diagnostic Trouble Codes (DTC) by initiating
the On Board Diagnostic (OBD) program
using the VAG 1551 Scan Tool (ST)
01-9 .
The DTC memory must be erased after the
malfunction has been repaired
37 .
A malfunction that affects oxygen sensor
control can only be read accurately after the
car has been driven for at least 10 minutes.
Malfunctions that can be attributed to a
temporary open circuit in the wiring, or a
loose terminal, will also be stored. These
malfunctions will be displayed as sporadic
malfunctions "SP" and are automatically
cancelled if they are not repeated after 40
engine starts.
Note:
The Malfunction Indicator Lamp (MIL) in the
instrument panel must light up when the
ignition is switched on and go off when the
engine is started (running). As long as
malfunctions occur in the monitored sensors
or components and the monitoring conditions
are met, the Malfunction Indicator Lamp lights
up even with the engine running.
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