Part 2

No CAN message was received from control unit N47-5 (ESP control unit).


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

Test 2.3.2.1.4.1: Test voltage supply of circuit 30.

Test 2.3.2.1.4.2: Test voltage supply of circuit 87.

2.3.2.1.4.1. 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

2.3.2.1.4.2. 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

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


2.3.2.1.6. 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

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


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


2.3.2.1.9. Check power supply at control unit A1 (Instrument cluster).
Note:If the fault code is not current, it may be deleted. In this case, the battery voltage was too low over an extended period.Charge the battery, if necessary.Question:Is the fault current in several control modules?Note:This fault could result in consequential faults. You should therefore process this fault first and then erase the fault memory.

YES
Possible cause and remedy

- Battery voltage too low.Test battery.Charge battery, replace if necessary.
- If fault occurs again:Check alternator.Communication with ECU required
- The quiescent current is too high.


NO
Test voltage supply Terminal 30.
Note

- Switch picture with function key F7
Test prerequisites

- Battery voltage is OK.
- Fuse F3f11A is OK.
Test sequence

- Switch off ignition.
- Disconnect connector at component A1 (Instrument cluster).
- Measure direct voltage with multimeter between sockets (A1) 1 and (A1) 4
Specified value

- Voltage [11.0...14.5] V
Question: Is the measurement value OK?













YES
The measurement value is OK.Possible cause and remedy

- Perform inspection of connector and of socket for bent pins and enlarged contacts.
End of test

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

- Check lines from control module F3 (Cockpit fuse box) to component A1 (Instrument cluster) against wiring diagram.
- Line from component A1 (Instrument cluster) to component W29/2 (Ground (right A pillar))
End of test







2.3.2.1.10. Check power supply at control unit A76 (Left front reversible emergency tensioning retractor).
If the fault code is not current, it may be deleted. In this case, the battery voltage was too low over an extended period.Charge the battery, if necessary.Note:This fault could result in consequential faults. You should therefore process this fault first and then erase the fault memory.Question:Is the fault current in several control modules?

YES
Possible cause and remedy

- Battery voltage too low.Test battery.Charge battery, replace if necessary.
- The quiescent current is too high.Test quiescent current.
- If fault occurs again:Check alternator.
Do you want to continue with function 'Alternator test'?

YES
Note on alternator test; Depending on the engine variant, different alternators are installed.

- Alternators without networking
- Alternators networked with engine control unit
Networked alternators can be diagnosed via the engine control unit.Detailed information on alternator testing can be found in WIS.Press button F2 to go to WIS documents

2.3.2.1.10. No further information available.


NO

2.3.2.1.10. No further information available.


NO
Test sequence

- Switch off ignition.
- Disconnect coupling 1 at component A76 (Left front reversible emergency tensioning retractor).
- Measurement at connector 1
- Measure direct voltage with multimeter between sockets (A76) 1.5 and (A76) 1.4
- Measure direct voltage with multimeter between sockets (A76) 1.5 and (A76) 1.6
Specified value

- Voltage[11.0 ... 14.5] V
Question

- Is the measurement value OK?


YES
The measurement value is OK.This test did not produce any clear result.Possible cause and remedy

- Inspect connector 1 at control unit A76 (Left front reversible emergency tensioning retractor) for damage, correct connection, loose contact and corrosion and repair, if necessary.
- A76 (Left front reversible emergency tensioning retractor)
End of test

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

- Line between component A76 (Left front reversible emergency tensioning retractor) and component F4f29 (Fuse 29)
- Line between component A76 (Left front reversible emergency tensioning retractor) and component W17/1 (Ground, left rear seat)
End of test

2.3.2.1.11. Check power supply at control unit A76/1 (Right front reversible emergency tensioning retractor).
If the fault code is not current, it may be deleted. In this case, the battery voltage was too low over an extended period.Charge the battery, if necessary.Note:This fault could result in consequential faults. You should therefore process this fault first and then erase the fault memory.Question:Is the fault current in several control modules?

YES
Possible cause and remedy

- Battery voltage too low.Test battery.Charge battery, replace if necessary.
- The quiescent current is too high.Test quiescent current.
- If fault occurs again:Check alternator.
Do you want to continue with function 'Alternator test'?

YES
Note on alternator test; Depending on the engine variant, different alternators are installed.

- Alternators without networking
- Alternators networked with engine control unit
Networked alternators can be diagnosed via the engine control unit.Detailed information on alternator testing can be found in WIS.Press button F2 to go to WIS documents

2.3.2.1.11. No further information available.


NO

2.3.2.1.11. No further information available.


NO
Test sequence

- Switch off ignition.
- Disconnect coupling 1 at component A76/1 (Right front reversible emergency tensioning retractor).
- Measurement at connector 1
- Measure direct voltage with multimeter between sockets (A76/1) 1.5 and (A76/1) 1.4
- Measure direct voltage with multimeter between sockets (A76/1) 1.5 and (A76/1) 1.6
Specified value

- Voltage[11.0 ... 14.5] V
Question

- Is the measurement value OK?


YES
The measurement value is OK.This test did not produce any clear result.Possible cause and remedy

- Inspect connector 1 at control unit A76/1 (Right front reversible emergency tensioning retractor) for damage, correct connection, loose contact and corrosion and repair, if necessary.
- A76/1 (Right front reversible emergency tensioning retractor)
End of test

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

- Line between component A76/1 (Right front reversible emergency tensioning retractor) and component F4f24 (Fuse 24)
- Line between component A76/1 (Right front reversible emergency tensioning retractor) and component W17 (Ground, right rear seat)
End of test

2.3.2.1.12. Check power supply at control unit A80 (Intelligent servo module for DIRECT SELECT).
Operation number of operation texts and work units or standard texts and flat rates:27-0641Test sequence

- Switch off ignition.
- Disconnect connector at component N15/5 (Electronic selector lever module control unit).
- Switch on ignition.
- Measure direct voltage with multimeter between 5 and 4
Specified value

- Voltage[7.0...16.0] V
Question

- Is the measurement value OK?







YES
The measurement value is OK.Possible cause and remedy

- Replace component A80 (Intelligent servo module for DIRECT SELECT).
Additional measures

- Perform initial startup.
- Continue with button "F2"







Initial startup
The following procedure will guide you through all steps required to perform a complete initial startup of system ISM.Preconditions

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

- Detach transport protection.
- Perform calibration.
- Personalizing
- Activating
Start process with button F2.

Warning!Communication with ECU required.


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

- Check fuse f111 (voltage supply from control unit ISM) in component F58 (Engine compartment fuse and relay box).
- Check all affected plugs, connectors and electrical components for damage, loose contact, corrosion etc. and repair if necessary.
End of test







2.3.2.1.13. Check power supply at control unit A89 (DTR controller unit).
Check power supply at control unit A89 (DTR controller unit).
Figure legend

- A89 (DTR controller unit)
Test prerequisite

- The voltage test at component G1 (Battery) is o.k.
- Fuse 117 in component F58 (Engine compartment fuse and relay box) is o.k.
Test sequence

- Switch off ignition.
- Detach coupling at component A89 (DTR controller unit).
- 1.Measure direct voltage with multimeter between sockets 1 and 1.6
- Switch on ignition.
Specified value

- [11.0 ... 14.5] V
Question

- Is the value o.k.?







YES
Note

- In the event of stored faults with a high fault frequency count or in the event of customer complaints, check lines and connectors for loose contact and corrosion..
End of test

NO
The measured value is not within the specified value range.Possible cause and remedy

- Cables between component F58 (Engine compartment fuse and relay box) and control module A89 (DTR controller unit)
- Plug connection MR4
End of test

2.3.2.1.14. Check power supply at control unit N2/7 (Restraint systems control unit).
Possible cause and remedy

- Overvoltage.Test battery.
- If fault occurs again:Check alternator.Communication with ECU required


2.3.2.1.15. Check power supply at control unit N3/9 (CDI control unit).

2.3.2.1.15. No further information available.


2.3.2.2. Resistance test of engine compartment CAN

Test 2.3.2.2.1: Test total resistance of engine compartment CAN.

Test 2.3.2.2.2: Test terminating resistor of component X30/19 (Voltage distributor connector (CAN C), front passenger).

Test 2.3.2.2.3: Test terminating resistor of CAN element in control module N3/9 (CDI control unit).

2.3.2.2.1. Test total resistance of engine compartment CAN.

Test 2.3.2.2.1.1: Perform measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger).

Test 2.3.2.2.1.2: Perform measurement at component N3/9 (CDI control unit).

2.3.2.2.1.1. 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

2.3.2.2.1.2. 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

2.3.2.2.2. 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

2.3.2.2.3. 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

2.3.2.3. Test procedure ground cable

Test 2.3.2.3.1: Measurement at component X30/19 (Voltage distributor connector (CAN C), front passenger)

Test 2.3.2.3.2: Measurement at component X30/46 (Rear end CAN C potential distributor connector)

2.3.2.3.1. 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

2.3.2.3.2. 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

2.3.3. 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 )