A3 Quattro V6-3.2L (BUB) (2008)
Information Bus: Testing and Inspection
CAN-Bus Terminal Resistance, Selector Lever To Motronic ECM, Checking
Special tools, testers and auxiliary items required
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Multimeter.
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Wiring diagram.
Test requirement
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A CAN-Bus malfunction was recognized.
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The Motronic Engine Control Module (ECM) J220 fuses OK.
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The Selector Lever E313 fuses OK.
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Battery voltage at least 12.5 volts.
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All electrical consumers such as, lights and rear window defroster, switched off.
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Vehicles with automatic transmission, shift selector lever into position "P" or "N".
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A/C switched off.
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Ground (GND) connections between engine/transmission/chassis OK.
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Ignition switched off.
Function
The Motronic Engine Control Module (ECM) J220 communicates with the Selector Lever E313.
The control modules are connected by two data bus wires which are twisted together (CAN_High and CAN_Low), and exchange information
(messages). Missing information on the CAN-bus is recognized as a malfunction by the Motronic Engine Control Module (ECM) J220 and the other
control modules connected to the CAN-bus.
Trouble-free operation of the CAN-Bus requires that it have a terminal resistance. This central terminal resistance is located in the Motronic Engine
Control Module (ECM) J220.
Test procedure
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Perform a preliminary check to verify the customers complaint. See: Testing and Inspection/Initial Inspection and Diagnostic Overview/General
Diagnosis
Start diagnosis
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Remove the selector mechanism, far enough to gain access to the Selector Lever E313 electrical harness connector - A -.
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Disconnect the Selector Lever E313 electrical harness connector - A -.