New Beetle L4-1.8L Turbo (AWV) (2005)
Information Bus: Testing and Inspection
Terminal Resistance For CAN-Bus, Checking
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
Test requirements
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A CAN-Bus malfunction was recognized via On Board Diagnostic (OBD). Diagnostic mode 3: Check DTC memory. See: Testing and
Inspection/Scan Tool Testing and Procedures/With Generic Scan Tool/Diagnostic Mode 3: Check DTC Memory
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Ignition switched off.
Test sequence
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Connect test box to Engine Control Module (ECM). connect test box for wiring test. See: Testing and Inspection/Reading and Clearing Diagnostic
Trouble Codes/Scan Tool Connecting/Test Box, Connecting For Wiring Test During this, wiring harness to Engine Control Module (ECM) is not
connected.
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Check the central termination resistor in the Engine Control Module (ECM):
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To do this, measure resistance between test box socket 58 + 60:
Specified value: 60.0 to 72.0 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 harness connector 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:
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To do this, perform 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 malfunction in Data-Bus wires or in other Data-Bus components according to wiring diagram.