Part 2

One or more signals sent from control unit Air conditioning via the CAN bus is implausible.

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

Test 1.1.3.2.1.8.1: Test voltage supply of circuit 30.

Test 1.1.3.2.1.8.2: Test voltage supply of circuit 87.

1.1.3.2.1.8.1. Test voltage supply of circuit 30.

Test 1.1.3.2.1.8.1.1: Test voltage of terminal 30 at control unit N51 (AIRmatic with ADS control module).

Test 1.1.3.2.1.8.1.2: Test procedure ground cable

Test 1.1.3.2.1.8.1.3: Test of cable for voltage supply

1.1.3.2.1.8.1.1. Test voltage of terminal 30 at control unit N51 (AIRmatic with ADS control module).
Test prerequisite

- Battery voltage is OK.
Status of the relevant actual values:
- Terminal 30:Warning! Communication with ECU required.
Test sequence

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

- Measure direct voltage with multimeter between sockets (2.21) 55 and (2.47) 81 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?

YES
The measurement value is OK.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 actual value is not o.k.Note

- This test did not produce any clear result.
- Select further tests.

1.1.3.2.1.8.1.2. Test procedure ground cable
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.

- W15/Measure resistance with multimeter between 1 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.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 measurement value is not OK.Possible cause and remedy

- Ground cable
- W15/1 (Ground (right footwell))
End of test

1.1.3.2.1.8.1.3. Test of cable for voltage supply
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 (2.47) 81 of the 126-pole socket box tester.
Specified value

- [11...14 V]
Question

- Is the measurement value OK?

YES
The measurement value is OK.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 measurement value is not OK.Possible cause and remedy

- Lines to component N51 (AIRmatic with ADS control module)
- F34f37 (Fuse 37)
End of test

1.1.3.2.1.8.2. Test voltage supply of circuit 87.

Test 1.1.3.2.1.8.2.1: Test voltage of terminal 87 at control unit N51 (AIRmatic with ADS control module).

Test 1.1.3.2.1.8.2.2: Test of cable for voltage supply

Test 1.1.3.2.1.8.2.3: Test procedure ground cable

1.1.3.2.1.8.2.1. Test voltage of terminal 87 at control unit N51 (AIRmatic with ADS control module).
Test 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.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 actual value is not o.k.Note

- This test did not produce any clear result.
- Select further tests.

1.1.3.2.1.8.2.2. Test of cable for voltage supply
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
The measurement value is OK.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 measurement value is not OK.Possible cause and remedy

- Lines to component N51 (AIRmatic with ADS control module)
- N10/1f45 (Fuse 45)
End of test

1.1.3.2.1.8.2.3. Test procedure ground cable
Test prerequisite

- Battery voltage is OK.
Test sequence

- Switch off ignition.
- Connect socket box.

- W15/Measure resistance with multimeter between 1 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.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 measurement value is not OK.Possible cause and remedy

- Ground cable
- W15/1 (Ground (right footwell))
End of test

1.1.3.2.1.9. Check power supply at control unit N63/1 (DTR control module).
Check power supply at control unit N63/1 (DTR control module).
Test sequence

- Switch off ignition.
- Disconnect coupling 2 at component N63/1 (DTR control module).
- Measure direct voltage with multimeter between sockets (N63/1) 2.8 and (N63/1) 2.4
- 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 N10/1 (Driver-side SAM control unit with fuse and relay module) and control module N63/1 (DTR control module)5A
- Cable for voltage supply

1.1.3.2.1.10. Check power supply at control unit N71 (Headlamp range adjustment control module).
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 there a current undervoltage fault is 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.Test quiescent current.

NO
Figure legend 1:N71 (Headlamp range adjustment control module)Figure legend 2:N10/1 (Driver-side SAM control unit with fuse and relay module)Test prerequisite

- The relevant actual value is not okay.
- Battery voltage is OK.
- Fuse N10/1f52 (Fuse 52) is OK.
Test sequence

- Switch off ignition.
- Disconnect connector at component N71 (Headlamp range adjustment control module).
- Measure direct voltage with multimeter between sockets (N71) 20 and (N71) 19
- Switch on ignition.
Specified value:Voltage = [11.0...14.5] VQuestion

- Is the measurement value OK?

YES
The measurement value is OK.Figure legend 1:N71 (Headlamp range adjustment control module)Figure legend 2:N10/1 (Driver-side SAM control unit with fuse and relay module)Possible cause or remedy in case of malfunction

- Inspect plug connections N71x1 and (N10/1) I10 for damage, loose contact and corrosion, and repair if necessary.
- N71 (Headlamp range adjustment control module)
End of test

NO
The measurement value is not OK.Figure legend 1:N71 (Headlamp range adjustment control module)Figure legend 2:N10/1 (Driver-side SAM control unit with fuse and relay module)Possible cause and remedy

- Cable (N10/1) I10.3 - (N71) 19 is faulty .
- Cable (N71) 20 - W15/1 (Ground (right footwell)) is faulty .
- N10/1 (Driver-side SAM control unit with fuse and relay module)
End of test

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

- Battery voltage is OK.
- Fuse F34f29 (Fuse 29) is OK.
Status of relevant actual value:
- Power supply:Warning! Communication with ECU required.
Specified value

- Power supply [11.0...14.5] V
Question

- Is the actual value o.k.?

YES
The actual value is okay.Possible cause and remedy

- 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..
- Check alternator.
End of test

NO
The actual value is not o.k.Test sequence

- Switch off ignition.
- Detach sockets A and C at component N73 (EIS [EZS] control unit).
- Measure direct voltage with multimeter between sockets (N73) B.2 and (N73) C.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,C at control unit N73 (EIS [EZS] control unit) for damage, correct connection, loose contact and corrosion and repair, if necessary.
- N73 (EIS [EZS] control unit)
End of test

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

- Check lines between components N73 (EIS [EZS] control unit) and N10/1 (Driver-side SAM control unit with fuse and relay module) and repair or replace if necessary.
- Fuse and component F34 (Interior fuse box)
Continue with button F2

Possible cause and remedy

- Check component N10/1 (Driver-side SAM control unit with fuse and relay module).
Question

- Continue troubleshooting in control unit N10/1 (Driver-side SAM control unit with fuse and relay module)?

1.1.3.2.1.11. No further information available.

1.1.3.2.1.12. Check power supply at control unit N80 (Steering column module).
Manual check of supply voltage
Test prerequisite

- The fuses are OK.
- One of the fault codes 9010/9011 is present, or the associated actual value is not OK.
Test sequence

- Remove component N80 (Steering column module).
- Disconnect connector A at component N80 (Steering column module).
- Switch on ignition.
- Measure direct voltage with multimeter between sockets [N80] A.8 and [N80] A.9
Specified value

- Voltage [11.0...14.5] V
Question

- Is the measurement value OK?

YES
The measurement value is OK.Possible cause and remedy

- Inspect connector A at control unit N80 (Steering column module) for damage, correct connection, loose contact and corrosion and repair, if necessary.
- Otherwise select further tests.
End of test

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

- Line between component N80 (Steering column module) and component N10/1 (Driver-side SAM control unit with fuse and relay module)
- Z7/58 (Circuit 30 connector sleeve)
- Line between component N80 (Steering column module) and component W15/1 (Ground (right footwell))
- Z6 (Ground connector sleeve)
- N10/1 (Driver-side SAM control unit with fuse and relay module)
End of test

1.1.3.2.1.13. Check power supply at control unit Y3/8n4 (Fully integrated transmission control (VGS) control unit).
Operation number of operation texts and work units or standard texts and flat rates:27-0641Test prerequisite

- Battery voltage is OK.
- Fuse N10/1f46 (Fuse 46) in component N10/1 (Driver-side SAM control unit with fuse and relay module) is o.k.
Test sequence

- Switch off ignition.
- Separate plug connection at transmission.
- Measure voltage in transmission wiring harness using a multimeter.
- Switch on ignition.
Measure direct voltage with multimeter between 5 and 4Specified value

- Voltage [8,5...16,4] V
Question

- Is the measurement value OK?

YES
The measurement value is OK.Further causes

- The diagnosis line is not OK
- Perform test on diagnosis line.
Press button "F2" for further tests

Test K cable to control unit Y3/8n4 (Fully integrated transmission control (VGS) control unit).
Operation number of operation texts and work units or standard texts and flat rates:27-0641Test prerequisite

- The power supply of component Y3/8n4 (Fully integrated transmission control (VGS) control unit) is OK.
Test sequence

- Switch on ignition.
- Test voltage at component X11/4 (Diagnosis test connector).
- If several control modules are connected to a K-wire, the voltage can be measured even if an open circuit exists.
Measure direct voltage with multimeter between (X11/4) 11 and (-) ground.Specified value

- Voltage [8,5...16,4] V
Question

- Is the measurement value OK?

YES
Test sequence

- Switch off ignition.
- Separate plug connection at transmission.
- Measure voltage in transmission wiring harness using a multimeter.

- Measure resistance with multimeter between ground and 3
Specified value

- Resistance measured: [OL] ohms
Question

- Is the measurement value OK?

YES
Further image can be displayed with key F7.X11/4 (Diagnosis test connector)Test sequence

- Switch off ignition.
- Separate plug connection at transmission.
- Measure voltage in transmission wiring harness using a multimeter.

- Measure resistance with multimeter between 3 and 11 (X11/4)
Specified value

- Resistance measured: [< 0,6] ohms
Question

- Is the measurement value OK?

YES
The measurement value is OK.Cause

- Control module has an internal error.
REMEDY

- Disassemble and assemble automatic transmission using the repair instructions.
- Exchange electrohydraulic control unit.
IMPORTANT NOTEFollowing the repair measures, the following checks MUST be carried out using the Diagnosis Assistance System, menu 'Control unit adaptations'

- Flash programming of control unit Y3/8n4 (Fully integrated transmission control (VGS) control unit)
- SCN coding
End of test

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

- Diagnostic cable has short to ground.
- Inspect wiring and connectors at connection points for loose contacts, damage and corrosion. Repair or replace as required.
End of test

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

- Diagnostic cable has open circuit.
- Inspect wiring and connectors at connection points for loose contacts, damage and corrosion. Repair or replace as required.
End of test

NO
The measurement value is not OK.Further causes

- Voltage supply line is not OK.
Press button "F2" for further tests

1.1.3.2.1.13. No further information available.

1.1.3.2.2. Resistance test of engine compartment CAN

Test 1.1.3.2.2.1: Test total resistance of engine compartment CAN.

Test 1.1.3.2.2.2: Test terminating resistor of component X30/5 (Left voltage distributor (CAN) connector).

Test 1.1.3.2.2.3: Test terminating resistor of CAN element in control module N3/10 (ME-SFI [ME] control unit).

1.1.3.2.2.1. Test total resistance of engine compartment CAN.

Test 1.1.3.2.2.1.1: Perform measurement at component X30/5 (Left voltage distributor (CAN) connector).

Test 1.1.3.2.2.1.2: Perform measurement at component N3/10 (ME-SFI [ME] control unit).

1.1.3.2.2.1.1. Perform measurement at component X30/5 (Left voltage distributor (CAN) connector).
Test total resistance of engine compartment CAN.
Figure legend

- X30/5 (Left voltage distributor (CAN) connector)
Test sequence

- Switch off ignition.
- Measurement with multimeter
- (X30/5) 2.Measure resistance with multimeter between pins 2 and 2.1 (X30/5)
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 N3/10 (ME-SFI [ME] control unit) to component X30/5 (Left voltage distributor (CAN) connector)
- Test terminating resistor of component X30/5 (Left voltage distributor (CAN) connector).
- Test terminating resistor of CAN element in control module N3/10 (ME-SFI [ME] control unit).
End of test

1.1.3.2.2.1.2. Perform measurement at component N3/10 (ME-SFI [ME] control unit).
Test total resistance of the CAN engine.
Test sequence

- Switch off ignition.
- Connect socket box to component N3/10 (ME-SFI [ME] control unit).
- Measure resistance with multimeter between sockets (F.41) 11 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 N3/10 (ME-SFI [ME] control unit) to component X30/5 (Left voltage distributor (CAN) connector)
- Test terminating resistor of component X30/5 (Left voltage distributor (CAN) connector).
- Test terminating resistor of CAN element in control module N3/10 (ME-SFI [ME] control unit).
End of test

1.1.3.2.2.2. Test terminating resistor of component X30/5 (Left voltage distributor (CAN) connector).
Test terminating resistor of component X30/5 (Left voltage distributor (CAN) connector).
Test sequence

- Switch off ignition.
- Connect socket box to component N3/10 (ME-SFI [ME] control unit).
- Disconnect coupling F at component N3/10 (ME-SFI [ME] control unit).
- Measure resistance with multimeter between sockets (F.41) 11 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 X30/5 (Left voltage distributor (CAN) connector) to component N3/10 (ME-SFI [ME] control unit)
- Component X30/5 (Left voltage distributor (CAN) connector)
End of test

1.1.3.2.2.3. Test terminating resistor of CAN element in control module N3/10 (ME-SFI [ME] control unit).
Test terminating resistor of component N3/10 (ME-SFI [ME] control unit).
Test sequence

- Switch off ignition.
- Connect socket box to component N3/10 (ME-SFI [ME] 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.41) 11 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 N3/10 (ME-SFI [ME] control unit)
End of test

1.1.3.3. 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 X30/5 (Left voltage distributor (CAN) connector)
- Observe level voltage.
- Plug in connector again at connector strip X30/5 (Left voltage distributor (CAN) connector).
- 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

- X30/5 (Left voltage distributor (CAN) connector)
- Test connectors and wiring for CAN of engine compartment CAN control modules.
- Control unit
Communication with ECU required ( Measuring system )

1.1.3.4. Display CAN signals with the aid of the special tool 'Star Diagnosis CANtool'.
Important notes

- When CAN diagnosis is finished, the 8-pin CAN cable must be replaced with the diagnostic cable.
- Before values are read out from a control unit, the control unit must be reinitialized.
Continue with button F2

Test 1.1.3.4.1: Actual values via CAN ( Engine CAN bus )

1.1.3.4.1. Actual values via CAN ( Engine CAN bus )
Note

- The actual values shown on the following screens are only displayed and updated as long as the CAN bus is active.
Continue with button F2

Test 1.1.3.4.1.1: Function-specific actual values :

Test 1.1.3.4.1.2: Cruise control

Test 1.1.3.4.1.3: Drive authorization

Test 1.1.3.4.1.4: Control unit-specific actual values :

Test 1.1.3.4.1.5: Electronic selector module

Test 1.1.3.4.1.6: Transmission control

Test 1.1.3.4.1.7: Motor electronics

Test 1.1.3.4.1.8: Steering column module

1.1.3.4.1.1. Function-specific actual values :

1.1.3.4.1.1. No further information available.

1.1.3.4.1.2. Cruise control
Warning!Communication with ECU required.

1.1.3.4.1.3. Drive authorization
Warning!Communication with ECU required.

1.1.3.4.1.4. Control unit-specific actual values :

1.1.3.4.1.4. No further information available.

1.1.3.4.1.5. Electronic selector module
Warning!Communication with ECU required.

1.1.3.4.1.6. Transmission control
Warning!Communication with ECU required.

1.1.3.4.1.7. Motor electronics
Warning!Communication with ECU required.

1.1.3.4.1.8. Steering column module
Warning!Communication with ECU required.

2. Check component N22 (AAC [KLA] control and operating unit).
Read and process fault code from control module N22 (AAC [KLA] control and operating unit).
Possible cause and remedy

- Read and process fault code from control module N22 (AAC [KLA] control and operating unit).
End of test