Golf L4-20L (BEV) (2004) Information Bus Component Diagrams
Information Bus: Testing and Inspection
Terminal Resistance For CAN-Bus, Checking (vehicles With Engine Code AVH, AZG, BBW, BEV)
Function
The Engine Control Module (ECM) communicates with all databus-capable control modules via a CAN databus.
These databus-capable control modules are connected via two data bus wires which are twisted together (CAN_High and CAN_Low), and exchange
information (messages). Missing information on the databus is recognized as a malfunction and stored.
Trouble-free operation of the CAN-Bus requires that it have a terminal resistance. This central terminal resistor is located in the Engine Control Module
(ECM).
Recommended special tools and equipment
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V.A.G 1526 multimeter or V.A.G 1715 multimeter
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V.A.G 1594 connector test kit
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Wiring diagram
Requirement
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Ignition switched off.
Work sequence
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Connect test box to Engine Control Module (ECM), connect test box for wiring test. During this, wiring harness to Engine Control Module (ECM)
is not connected. See: Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool Connecting/Test Box, Connecting For
Wiring Test
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Check central termination resistor in Engine Control Module (ECM) by measuring resistance between test box socket 58 + 60:
Specified value: 60 to 72 Ohms
If resistance value is not in specified range:
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Replace Motronic Engine Control Module (ECM) -J220-.
If resistance value is in specified range:
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Disconnect test box from Engine Control Module (ECM).
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Connect test box to control module wiring harness.
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Check CAN data bus wires for shorts among one another by performing a resistance measurement between test box sockets 58 + 60:
Specified value: Infinite Ohms
If specified value is obtained (wires have no shorts):
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Eliminate error in wires (see circuit diagram).