New Beetle L4-2.0L (AZG) (2003)
CAN-Bus Checking
CAN-Bus, Checking
Function
The engine control module communicates with all control modules capable of data bus via CAN- Bus.
The control modules capable of CAN-Bus are connected together via two data bus wires twisted together (CAN high and CAN low) and exchange
information (messages). Information not available in the CAN-Bus will be recognized as a fault by the engine control module as well as other CAN-Bus
control modules.
The CAN-Bus requires a matching resistor to function fault free. This central matching resistor is located in the engine control module.
NOTE: You can read out which control modules are actively connected via CAN-Bus to the engine control module in measured value blocks 125 and
126. Refer to "Scan Tool Testing/Measuring Value Blocks/Evaluating Measured Value Blocks/Display Groups 120 to 129 (Communication)" See:
Testing and Inspection
Test conditions
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A malfunction has been recognized by the CAN-Bus On Board Diagnostic (OBD)
Special tools and equipment
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Test box V.A.G 1598/31
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Hand multimeter VAG 1526 or multimeter VAG 1715
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Adapter set VAG 1594
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Wiring diagram
Test sequence
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Switch ignition off.
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Remove inner plenum chamber cover left:
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Unlock engine control module connector and disconnect.
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Connect test box V.A.G 1598/31 to engine control module. Control module wiring harness is not connected by this action.
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Check centralized matching resistor in engine control module.
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Perform a resistance measurement between test box sockets:
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Sockets 58 + 60
Specification: 60 - 72 Ohms
If the resistance value is outside the specified range:
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Replace Engine Control Module (ECM).
If the resistance value is within the specified range:
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Repair fault in wiring using wiring diagram:
Terminal Resistance For CAN-Bus, Checking
Checking Terminal Resistance For CAN Bus (Vehicles With Engine Code AVH, AZG, BDC)