With Generic Scan Tool
Terminal Resistance For CAN-Bus, Checking
Function
Control module for Diesel-Direct fuel injection system communicates with other CAN-Bus capable control modules.
The databus-capable control modules are connected via two databus wires which are twisted together (CAN_High and CAN_Low), and exchange information (messages). Missing information on the data bus is recognized as an error by both the control module for Diesel-Direct fuel injection system and by other CAN-Bus control modules.
Trouble-free operation of the CAN-Bus requires that it have a terminal resistance. This central termination resistor is located in control module for Diesel-Direct fuel injection system.
Recommended special tools and equipment
- V.A.G 1598/18 Adapter - 68-pin (vehicles with 80-pin control module and auto. transmission)
- V.A.G 1598/21 Adapter for V.A.G 1598 (25-pin) (vehicles with 80-pin control module and manual transmission)
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram
Requirements
- DTC "P0600 Data Bus Power train missing message" was detected by the control module for Diesel-Direct fuel injection system. Diagnostic mode 3: Check DTC memory. Diagnostic Mode 3: Check DTC Memory
- Ignition switched off.
Test sequence
Vehicles with 80-pin control module and manual transmission
Vehicles with 80-pin control module and auto. transmission.
- Remove air filter housing.
- Disengage connector from ABS control module and disconnect.
- Connect V.A.G1598/21 -1- test box to ABS control module wiring harness -2-
- Check terminal resistance in control module for Diesel-Direct fuel injection system:
- To do this, measure resistance between test box sockets 10 + 11:
Specified value: 115 to 135 Ohms
If resistance value is not in specified range:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If resistance value is in specified range:
- Check CAN data bus wires for shorts among one another:
- Remove inner plenum chamber cover:
- Disengage connector from control module for Diesel-Direct fuel injection system and disconnect the connector.
- Measure resistance again between test box sockets 10 + 11:
Specified value: Infinite Ohms
If specified value is obtained (wires have no shorts):
- Eliminate error in wires (see circuit diagram).
- Erase DTC memory of control module for Diesel-Direct fuel injection system. Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
Vehicles with 80-pin control module and auto. transmission
- Remove inner plenum chamber cover.
- Then open locking mechanism of connector in -direction of arrow- and disconnect connector from Transmission Control Module (TCM).
- Connect V.A.G 1598/18 Adapter - 68-pin to wiring harness of Transmission Control Module (TCM) -1- and engage the connector -2-.
- Check CAN-Bus wires with termination resistors in ECM and ABS control module:
- To do this, measure resistance between test box sockets 3 +25:
Specified value: 55 to 75 Ohms
If resistance value is not in specified range:
- Continue test according to the following table:
If resistance value is in specified range:
- Check CAN data bus wires for shorts among one another:
- Disengage connector from control module for Diesel-Direct fuel injection system and disconnect the connector.
- Remove air filter housing.
- Disengage connector from ABS control module and disconnect.
- Measure resistance again between test box sockets 3 + 25:
Specified value: Infinite Ohms
If specified value is obtained (wires have no shorts):
- Eliminate error in wires (see circuit diagram):
Continuation at 115 to 135 Ohms
- Disengage connector from control module for Diesel-Direct fuel injection system and disconnect the connector.
- Check CAN-Bus wires with termination resistor in ABS control module:
- To do so, measure resistance again between test box sockets 3 + 25:
Specified value: 115 to 135 Ohms
If resistance value is not in specified range:
- Check CAN-Bus wires.
If wires to ABS control module are OK:
- Replace ABS control module.
- Erase DTC memory of control module for Diesel-Direct fuel injection system. Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If resistance value is in specified range:
- Re-connect connectors to control module for Diesel-Direct fuel injection system.
- Remove air filter housing.
- Disengage connector from ABS control module and disconnect.
- Check CAN-Bus wires with termination resistor in control module for Diesel-Direct fuel injection system:
- To do so, measure resistance anew between test box sockets 3 + 25:
Specified value: 115 to 135 Ohms
If resistance value is not in specified range:
- Check CAN-Bus wires.
If no malfunctions are found in wires:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.
- Generate readiness code.
Checking CAN-Bus wires
- Remove air filter housing.
- Disengage connector from ABS control module and disconnect.
- Disengage connector from control module for Diesel-Direct fuel injection system and disconnect the connector.
- Check CAN data bus wires for shorts among one another:
- To do so, measure resistance anew between test box sockets 3 + 25 at V.A.G 1598/18 Adapter - 68-pin:
Specified value: Infinite Ohms
If specified value is obtained (wires have shorts):
- Eliminate error in wires (see circuit diagram):
- Erase DTC memory of control module for Diesel-Direct fuel injection system. Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specified value is obtained (wires have no shorts):
- Connect test box to control module wiring harness. connect test box for wiring test.
- Check CAN-Bus wires between test box sockets for open circuits according to wiring diagram:
1598/22
1598/18
Socket 68 and
Socket 3
Socket 75 and
Socket 25
Wire resistance: max. 1.5 Ohms
- Check wires for short circuits to B+ or Ground (GND).
If no malfunctions are found in wires:
- Connect V.A.G1598/21 -1- test box to ABS control module wiring harness -2-
- Check CAN-Bus wires between test box sockets 1598/22 and 1598/21 for open circuits according to wiring diagram:
1598/22
1598/21
Socket 68 and
Socket 10
Socket 75 and
Socket 11
Wire resistance: max. 1.5 Ohms
Vehicles with 121-pin control module
- Connect test box to control module for Diesel-Direct fuel injection system. connect test box for wiring test. During this, wiring harness to Engine Control Module (ECM) is not connected.
- Check central terminal resistance in control module for Diesel-Direct fuel injection system:
- To do this, measure resistance between test box sockets 6+7.
Specified value: 60 to 72 Ohms
If resistance value is not in specified range:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.
- Generate readiness code.
If resistance value is in specified range:
- Eliminate error in wires (see circuit diagram):
Vehicles with 154-pin control module
- Connect adapter cable (V.A.G 1598/39-2) to test box (V.A.G 1598/42).
- Connect test box to control module for Diesel-Direct fuel injection system. connect test box for wiring test. During this, wiring harness to Engine Control Module (ECM) is not connected.
- Check central terminal resistance in control module for Diesel-Direct fuel injection system:
- To do this, measure resistance between test box sockets 66 + 89.
Specified value: approx. 66 Ohms
If resistance value is not in specified range:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If resistance value is in specified range:
- Eliminate error in wires (see circuit diagram).