A5 Quattro Coupe V6-3.2L (CALA) (2009)
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Engine Control Module: Testing and Inspection
CAN Bus Terminal Resistance, Checking
Diagnostic Procedures
CAN Bus Terminal Resistance, Checking
Observe all safety precautions: => [ Safety Precautions ] See: Service Precautions/Safety Precautions
View clean working conditions: => [ Clean Working Conditions ] See: Service Precautions/Clean Working Conditions
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.
Special tools, testers and auxiliary items required
‹› Multimeter
‹› Wiring diagram
Test requirement
‹› A CAN-Bus malfunction was recognized.
‹› The Motronic Engine Control Module (ECM) (J623) fuses OK.
‹› Battery voltage at least 12.5 volts.
‹› All electrical consumers such as, lights and rear window defroster, switched off.
‹› Vehicles with automatic transmission, shift selector lever into position " P" or "N".
‹› A/C switched off.
‹› Ground (GND) connections between engine/transmission/chassis OK.
‹› Ignition switched off.
Function
The Motronic Engine Control Module (ECM) (J623) communicates with other CAN-Bus capable control modules.
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) (J623) and the other
control modules connected to the CAN-bus.
