Part 1

One or more messages from control unit N80 (Steering column module) are not available on the CAN bus.

Possible cause:

Check the CAN communication with control unit N80 (Steering column module).
Interior CAN bus

Affected functions:
CAN Communication
Automatic transmission Function

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Test 1: Engine compartment CAN test

Test 2: Check the CAN communication with control unit N80 (Steering column module). Test 3: Interior CAN check

Engine compartment CAN test

Test 1.1: Procedure in case of CAN faults Test 1.2: Evaluation of CAN fault codes Test 1.3: Further CAN test options
1. Procedure in case of CAN faults
  
  Test 1.1.1: How do I quickly reach my goal? Test 1.1.2: General test information
  
  Test 1.1.3: General CAN fundamentals
  
  Test 1.1.4: Possible aids and their usage
  1. How do I quickly reach my goal?
    
    How do I quickly reach my goal?First call up menu item 'Evaluation of CAN fault codes' in case of CAN timeout fault codes and communication errors.The resulting tests must be performed.Menu item 'Further CAN test options' should only be called up if the above-specified tests do not produce the desired result.Note:Menu item 'General test information' can be called up for an explanation of the different CAN fault types.
  2. General test information
    
    Notes on CAN fault codes:CAN timeout fault
    - A CAN timeout fault code is set due to the absence of a CAN input signal.The cause of this may be not only the transmitter control unit, but also the CAN networking.
    - For example:No CAN message was received from control unit A. Bus OFF fault
    - A Bus OFF fault code is set, when the control unit cannot send a certain amount of messages to the CAN bus or the messages are incomplete.The control unit then switches off for a short time from CAN bus.
    - For example:CAN controller: CAN bus OFF Functional CAN fault
    - A functional CAN fault code is set because of an implausible CAN input signal.The cause of this is not the CAN networking, but the transmitter control unit or its sensors.
    - For example:CAN signal 'A' from control unit B is implausible.
      
      Notes on CAN faults that cannot be read out as fault codes.Bus wake-up event
    - An event that wakes up the bus without reason is designated a bus wake-up event.
    - The cause of this is not the CAN networking, but the transmitter control unit or its sensors.
    - Further possible causes of fault:
    - Magnetic fields caused by nearby high-voltage installations, railroad installations or power plants.
    - Magnetic fields can radiate on to lines and control units in rare cases and cause undefined behavior in the control units.
    - The special tool 'Star Diagnosis CANtool' can be used to log bus wake-up events, bus keepawake events and other signals.
      
      Bus keepawake event
    - When a control unit keeps communication on the bus awake without reason, this is designated a bus keepawake event.
    - The cause of this is not the CAN networking, but the transmitter control unit or its sensors.
    - Further possible causes of fault:
    - Magnetic fields caused by nearby high-voltage installations, railroad installations or power plants.
    - Magnetic fields can radiate on to lines and control units in rare cases and cause undefined behavior in the control units.
    - The special tool 'Star Diagnosis CANtool' can be used to log bus wake-up events, bus keepawake events and other signals.
      Legend and description for figure 1CAN-H: CAN bus HighCAN-L: CAN bus LowECU 1 ... n: Control unit 1 ... nLegend and description for figure 2U 1: Specification approx. 3,6 voltsU 2: Specification approx. 0 voltsU 3: Specification approx. 2,5 voltsU 4: Specification approx. 1,4 voltsU 5: Specification approx. 5 voltsContinue with button F2
      Legend and description for figure 1CAN-H: CAN bus HighCAN-L: CAN bus LowECU 1 ... n: Control unit 1 ... nCAN terminating resistor ( Example: 120ohms)Legend and description for figure 2U 1: Specification approx. 3,6 voltsU 2: Specification approx. 2,5 voltsU 3: Specification approx. 1,4 voltsContinue with button F2
      
      1.1.3.2. No further information available.
      1.1.4. No further information available.
      1.3.1.2. No further information available.
      Page 86
      1.3.2.1.5. No further information available.
      NO
      
      Test 1.3.2.1.10.1: The measurement value is not OK. Test 1.3.2.1.10.2: Possible cause and remedy
      
      Test 1.3.2.1.10.3: Test regulator and generator. 1.3.2.1.10.1. The measurement value is not OK. 1.3.2.1.10.1. No further information available.
      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
      
      1.3.2.1.10.3. No further information available.
      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
      Communication with ECU required ( Measuring system )
Check the CAN communication with control unit N80 (Steering column module). Warning!Communication with ECU required.
Interior CAN check Warning!Communication with ECU required.