Part 2

The request for fan output is implausible.



1.3.2.1.8. Check power supply at control unit N15/7 (Transfer case control module).
Test voltage supply of circuit 15.
Operation number of operation texts and work units or standard texts and flat rates:28-0641Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Disconnect connector "A" at component N15/7 (Transfer case control module).
- Measure voltage in transmission wiring harness using a multimeter.
- Switch on ignition.
Measure direct voltage with multimeter between 5 and 3Specified value

- Voltage [8,0...16,5] V
Question

- Is the measurement value OK?







YES
Preconditions

- The measurement value is OK.
Other possible cause of fault

- Open circuit in power supply (circuit 30)
Additional measures

- Test voltage supply of circuit 30.
Continue with button "F2"

Test voltage supply of circuit 30.
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Disconnect connector "A" at component N15/7 (Transfer case control module).
- Measure voltage in transmission wiring harness using a multimeter.
- Switch on ignition.
Measure direct voltage with multimeter between 5 and 6Specified value

- Voltage [8,0...16,5] V
Question

- Is the measurement value OK?







YES
Preconditions

- The measurement value is OK.
Possible cause

- Replace component N15/7 (Transfer case control module).
Additional measures

- Perform initial startup.
Continue with button "F2"







Test 1.3.2.1.8.1: Initial startup with manual settings input for new control unit( For example: The previous control unit can no longer be read. )

1.3.2.1.8.1. Initial startup with manual settings input for new control unit( For example: The previous control unit can no longer be read. )
Initial startup with manual settings input for new control unit
The following procedure will guide you through all steps required to perform a complete initial startup of system VG.Preconditions

- The new control unit must have already been installed.
You will be guided through the following steps

- Program control unit.
- Determine vehicle data for off-line SCN coding from the vehicle.
- Perform off-line SCN coding.
- Calibrate control unit Transfer case.
Start process with button F2.

Warning:- Connect battery charger.- Make sure that the diagnostic plug is properly seated in the diagnostic socket.- The diagnostic connector must remain plugged in to the vehicle.- Switch off all electrical consumers.- If possible, do not perform any procedures on the vehicle during control unit programming.

Warning!Communication with ECU required.

NO
Preconditions

- The measurement value is not OK.
Possible cause

- Check fuse F87 (voltage supply from control unit N15/7 (Transfer case control module)) in component F33 (Rear backup fuse box).
- Inspect wiring and connectors at connection points for loose contacts, corrosion, damage and short circuits. Repair or replace as required.
End of test







NO
The measurement value is not OK.Possible causes

- Fuse F57 in component F4 (Load compartment fuse and relay box)
- Lines and connectors are defective.
Remedy

- Check fuse F57 (voltage supply from control unit N15/7 (Transfer case control module)) in component F4 (Load compartment fuse and relay box).
- Inspect wiring and plug connections between F4 (Load compartment fuse and relay box) and control unit N15/7 (Transfer case control module) for corrosion, loose contacts and damage.
End of test







1.3.2.1.9. Check power supply at control unit N15/9 (Rear axle differential lock control unit).
Operation number of operation texts and work units or standard texts and flat rates:35-0641Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Disconnect connector at component N15/9 (Rear axle differential lock control unit).
- Measure voltage directly at the jacks of the wiring harness of the rear axle interwheel lock using a multimeter.
- Switch on ignition.
Measure direct voltage with multimeter between 47 and 46Specified value

- Voltage [9,0...16,0] V
Question

- Is the measured value within the specified value range?







YES
Test prerequisite

- The measurement value is OK.
Further test procedure

- Switch off ignition.
- Disconnect connector at component N15/9 (Rear axle differential lock control unit).
- Measure voltage directly at the jacks of the wiring harness of the rear axle interwheel lock using a multimeter.
- Switch on ignition.
Measure direct voltage with multimeter between 47 and 17Specified value

- Voltage [9,0...16,0] V
Question

- Is the measured value within the specified value range?







YES
Possible cause and remedy

- Internal fault in control unit
- Replace component N15/9 (Rear axle differential lock control unit).
Additional measures

- Perform initial startup.
Continue with button "F2"







Test 1.3.2.1.9.1: Initial startup with manual settings input for new control unit( For example: The previous control unit can no longer be read. )

1.3.2.1.9.1. Initial startup with manual settings input for new control unit( For example: The previous control unit can no longer be read. )
Initial startup with manual settings input for new control unit
The following procedure will guide you through all steps required to perform a complete initial startup of system VG.Preconditions

- The new control unit must have already been installed.
You will be guided through the following steps

- Program control unit.
Start process with button F2.

Warning:- Connect battery charger.- Make sure that the diagnostic plug is properly seated in the diagnostic socket.- The diagnostic connector must remain plugged in to the vehicle.- Switch off all electrical consumers.- If possible, do not perform any procedures on the vehicle during control unit programming.

Warning!Communication with ECU required.

NO
The measurement value is not OK.Possible causes

- Fuse F48 in component F4 (Load compartment fuse and relay box)
- Lines and connectors are defective.
Remedy

- Check fuse F48 (voltage supply from control unit N15/9 (Rear axle differential lock control unit)) in component F4 (Load compartment fuse and relay box).
- Inspect wiring and plug connections between F4 (Load compartment fuse and relay box) and control unit N15/9 (Rear axle differential lock control unit) for corrosion, loose contacts and damage.
NOTE

- After completing the repair work, always perform the following function check of system HAQ.
- After a successful function test is performed, the check is finished.
- If the function test was not successful, the possible causes and the measures to be taken will be shown.
Continue with button "F2"







Warning!Communication with ECU required.


NO
The measurement value is not OK.Possible causes

- Fuse F69 in component F4 (Load compartment fuse and relay box)
- Lines and connectors are defective.
Remedy

- Check fuse F69 (voltage supply from control unit N15/9 (Rear axle differential lock control unit)) in component F4 (Load compartment fuse and relay box).
- Inspect wiring and plug connections between F4 (Load compartment fuse and relay box) and control unit N15/9 (Rear axle differential lock control unit) for corrosion, loose contacts and damage.
NOTE

- After completing the repair work, always perform the following function check of system HAQ.
- After a successful function test is performed, the check is finished.
- If the function test was not successful, the possible causes and the measures to be taken will be shown.
Continue with button "F2"







Warning!Communication with ECU required.


1.3.2.1.10. Check power supply at control unit N47-5 (ESP control unit).
Operation number of operation texts and work units or standard texts and flat rates:42-0641Test prerequisite

- Battery voltage is OK.
- Fuse f115 in component F58 (Engine compartment fuse and relay box) is o.k.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between sockets (1.16) 16 and (1.4) 4 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N47-5 (ESP control unit)Test ground cable of component N47-5 (ESP control unit) for Loose contact.End of test

NO
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between ground and socket (1.4) 4 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.

- W Measure resistance with multimeter between 70 and (1.16) 16 of the 35-pole socket box tester.
Specified value

- [<1ohms ]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N47-5 (ESP control unit)Test ground cable of component N47-5 (ESP control unit) for Loose contact.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Ground cable
- W70 (Ground (ESP))
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check components Fuse, f 115 and F58 (Engine compartment fuse and relay box).
- Cable to component N47-5 (ESP control unit)
End of test

1.3.2.1.11. Check power supply at control unit N51 (AIRmatic with ADS control module).

Test 1.3.2.1.11.1: Test voltage supply of circuit 30.

Test 1.3.2.1.11.2: Test voltage supply of circuit 87.

1.3.2.1.11.1. Test voltage supply of circuit 30.
Operation number of operation texts and work units or standard texts and flat rates:42-0641Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between sockets (2.21) 55 and (2.43) 77 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N51 (AIRmatic with ADS control module)Test ground cable of component N51 (AIRmatic control unit) for Loose contact.End of test

NO
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between ground and socket (2.43) 77 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.

- W15/Measure resistance with multimeter between 2 and (2.21) 55 of the 35-pole socket box tester.
Specified value

- [<1ohms ]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N51 (AIRmatic with ADS control module)Test ground cable of component N51 (AIRmatic control unit) for Loose contact.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Ground cable
- W15/2 (Ground, left footwell)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check components Fuse, f 33 and F4 (Load compartment fuse and relay box).
- Cable to component N51 (AIRmatic with ADS control module)
End of test

1.3.2.1.11.2. Test voltage supply of circuit 87.
Operation number of operation texts and work units or standard texts and flat rates:42-0641Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between sockets (2.21) 55 and (2.43) 77 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N51 (AIRmatic with ADS control module)Test ground cable of component N51 (AIRmatic control unit) for Loose contact.End of test

NO
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.
- Switch on ignition.

- Measure direct voltage with multimeter between ground and socket (2.43) 77 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?


YES
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.

- W15/Measure resistance with multimeter between 2 and (2.21) 55 of the 35-pole socket box tester.
Specified value

- [<1ohms ]
Question

- Is the measurement value OK?


YES
The measurement value is OK.Supply line of component N51 (AIRmatic with ADS control module)Test ground cable of component N51 (AIRmatic control unit) for Loose contact.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Ground cable
- W15/2 (Ground, left footwell)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check components Fuse, f 33 and F4 (Load compartment fuse and relay box).
- Cable to component N51 (AIRmatic with ADS control module)
End of test

1.3.2.1.12. Check power supply at control unit N71 (HRA [LWR] control unit).
Warning!Communication with ECU required.


1.3.2.1.13. Check power supply at control unit N73 (EIS [EZS] control unit).
Test prerequisite

- Relevant fault codes are present, or communication with control module cannot be established.
- Fuse F3f14 (Fuse 14) is OK.
Test sequence

- Switch off ignition.
- Separate plug connection A at control unit N73 (EIS [EZS] control unit).
- Separate plug connection B at control unit N73 (EIS [EZS] control unit).
- Measure direct voltage with multimeter between sockets (N73) A.5 and (N73) A.6
- Measure direct voltage with multimeter between sockets (N73) B.2 and (N73) B.1
Specified value

- Voltage[11.0...14.5] V
Question

- Are the measurement values OK?


YES
The measurement values are OK.Possible cause and remedy

- Inspect connector B at control unit N70 (Overhead control panel control unit) for damage, correct connection, loose contact and corrosion and repair, if necessary.
- Inspect connector C at control unit N70 (Overhead control panel control unit) for damage, correct connection, loose contact and corrosion and repair, if necessary.
End of test

NO
The measurement values are not OK.Test sequence

- Measure direct voltage with multimeter between ground and socket (N73) A.6
- Measure direct voltage with multimeter between ground and socket (N73) B.1
Specified value

- Voltage[11.0...14.5] V
Question

- Is the measurement value OK?


YES
The measurement values are OK.Possible cause and remedy

- Ground line leading to control unit N73 (EIS [EZS] control unit)
End of test

NO
The measurement values are not OK.Possible cause and remedy

- Line between component 'F3f14 (Fuse 14)' and control unit N73 (EIS [EZS] control unit) faulty
- Line between component 'G1/7 (Auxiliary battery)' and control unit N73 (EIS [EZS] control unit) faulty
End of test

1.3.2.1.14. Check power supply at control unit N80 (Steering column module).
Warning!Communication with ECU required.


1.3.2.1.15. Check power supply at control unit Y3/8n4 (Fully integrated transmission control (VGS) control unit).
Warning!Communication with ECU required.


1.3.2.2. Resistance test of engine compartment CAN

Test 1.3.2.2.1: Test total resistance of engine compartment CAN.

Test 1.3.2.2.2: Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).

Test 1.3.2.2.3: Test terminating resistor of CAN element in control module N3/9 (CDI control unit).

1.3.2.2.1. Test total resistance of engine compartment CAN.

Test 1.3.2.2.1.1: Perform measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger).

Test 1.3.2.2.1.2: Perform measurement at component N3/9 (CDI control unit).

1.3.2.2.1.1. Perform measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger).
Test total resistance of engine compartment CAN.
Figure legend

- X30/19 (Voltage distributor connector (CAN C), front passenger)
Test sequence

- Switch off ignition.
- Measurement with multimeter
- (X30/19) 2.Measure resistance with multimeter between pins 2 and 2.1 (X30/19)
Adapter cable no. W220 589 00 99 36 may be used.Specified value

- [55...65]ohms
Question:

- Is the measured value within the specified value range?







YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Line from component N3/9 (CDI control unit) to component X30/19 (Voltage distributor connector (CAN C), front passenger)
- Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).
- Test terminating resistor of CAN element in control module N3/9 (CDI control unit).
End of test

1.3.2.2.1.2. Perform measurement at component N3/9 (CDI control unit).
Test total resistance of the CAN engine.
Test sequence

- Switch off ignition.
- Connect socket box to component N3/9 (CDI control unit).
- Measure resistance with multimeter between sockets (F.53) 23 and (F.54) 24 of the 35-pole socket box tester.
Specified value

- Resistor[55...65]ohms
Question

- Is the measurement value OK?


YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Line from component N3/9 (CDI control unit) to component X30/19 (Voltage distributor connector (CAN C), front passenger)
- Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).
- Test terminating resistor of CAN element in control module N3/9 (CDI control unit).
End of test

1.3.2.2.2. Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).
Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).
Test sequence

- Switch off ignition.
- Connect socket box to component N3/9 (CDI control unit).
- Disconnect coupling F at component N3/9 (CDI control unit).
- Measure resistance with multimeter between sockets (F.53) 23 and (F.54) 24 of the 35-pole socket box tester.
Specified value

- Resistor[115...125]ohms
Question

- Is the measurement value OK?


YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Line from component X30/19 (Voltage distributor connector (CAN C), front passenger) to component N3/9 (CDI control unit)
- Component X30/19 (Voltage distributor connector (CAN C), front passenger)
End of test

1.3.2.2.3. Test terminating resistor of CAN element in control module N3/9 (CDI control unit).
Test terminating resistor of component N3/9 (CDI control unit).
Test sequence

- Switch off ignition.
- Connect socket box to component N3/9 (CDI control unit).
- Connector F is plugged in at control unit.
- Unplug the socket F from the wiring harness at the socket box.
- Measure resistance with multimeter between sockets (F.53) 23 and (F.54) 24 of the 35-pole socket box tester.
Specified value

- Resistor[115...125]ohms
Question

- Is the measurement value OK?


YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Control unit N3/9 (CDI control unit)
End of test

1.3.2.3. Test procedure ground cable

Test 1.3.2.3.1: Measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger)

Test 1.3.2.3.2: Measurement at component X30/46 (Rear end CAN C potential distributor connector)

1.3.2.3.1. Measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger)
Test procedure ground cable
Figure legend

- Component X30/19 (Voltage distributor connector (CAN C), front passenger) is located in the front passenger footwell.
Test sequence

- Switch off ignition.
- Measurement with multimeter
- Unplug connector at component.
- Measure resistance with multimeter between socket (X30/19) 13.3 and ground (Kl. 31)
Specified value

- [< 5]ohms
Question:

- Is the measured value within the specified value range?













YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test

1.3.2.3.2. Measurement at component X30/46 (Rear end CAN C potential distributor connector)
Test procedure ground cable
Figure legend

- Component X30/46 (Rear end CAN C potential distributor connector) is located behind the paneling in the left rear wheelhouse.
Test prerequisite

- Special equipment 'Code 430 (Offroad engineering package)' or 'Code 475 (Tire pressure monitor)' is installed.
Test sequence

- Switch off ignition.
- Measurement with multimeter
- Unplug connector at component.
- Measure resistance with multimeter between socket (X30/46) 1.3 and ground (Kl. 31)
Specified value

- [< 5]ohms
Question:

- Is the measured value within the specified value range?













YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test

1.3.3. Test with the aid of the measuring system
Test sequence

- Measurement of level voltage of engine CAN buses CAN bus High and CAN bus Low with the universal oscilloscope
- Separating one user from the connector strip X30/19 (Voltage distributor connector (CAN C), front passenger)
- Observe level voltage.
- Plug in connector again at connector strip X30/19 (Voltage distributor connector (CAN C), front passenger).
- Repeat this procedure for all CAN users.
Specified value

- As soon as the faulty branch was disconnected, the current image of the level voltage changes.
Possible cause of fault in the faulty branch

- X30/19 (Voltage distributor connector (CAN C), front passenger)
- Test connectors and wiring for CAN of engine compartment CAN control modules.
- Control unit
Communication with ECU required ( Measuring system )