Rabbit L5-2.5L (BGP) (2006)
Engine Control Module: Component Tests and General Diagnostics
CAN-Bus Terminal Resistance, Direct Shift Gearbox (DSG) Mechatronic J743 to Motronic Engine
Control Module J623, Checking
CAN-Bus Terminal Resistance, Direct Shift Gearbox (DSG) Mechatronic J743 To Motronic Engine Control Module (ECM) J623 , 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) J623 Direct Shift Gearbox (DSG) Mechatronic J743 fuses OK.
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The Direct Shift Gearbox (DSG) Mechatronic J743 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) 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.
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) J623.
Procedure
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Disconnect the Direct Shift Gearbox (DSG) Mechatronic J743 electrical harness connector.
NOTE: The Motronic Engine Control Module (ECM) J623 must remain connected for the following step.
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Using a Multimeter, check the Direct Shift Gearbox (DSG) Mechatronic J743 electrical harness connector terminals 10 to 15 for resistance.
Specified value: 60 to 72 Ohms (at approx. 20 degrees C)
If the specified value was not obtained:
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Check the wiring connection for an open circuit, short circuit to Battery (+) or Ground (GND).
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Check the wiring connection for damage, corrosion, lose or broken terminals.
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If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring:
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Replace the Motronic Engine Control Module (ECM) J623.