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Home >> Jeep >> 2023 >> Grand Cherokee Laredo, AWD >> Repair and Diagnosis >> General Information >> OEM General Information >> (Security Gateway Module (SGW) Electrical Diagnostics) >> DTC Troubleshooting >> U009B-00 ETHERNET Bus 4 >> Diagnostic Test

Diagnostic Test

  1. DETERMINE THE AUTOMOTIVE ETHERNET NETWORK NEEDING SERVICE 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
      NOTE:

      For this DTC to appear ACTIVE, the Automotive Ethernet ECU must be communicating on a CAN identified by a YELLOW Icon  . An Automotive Ethernet ECU that is communicating on a CAN without an ACTIVE DTC is identified by a BLUE Icon  .

    3. Using the Automotive Ethernet Systems table and wiring diagrams, determine the Automotive Ethernet network Commander and Responder ECUs with the communication concern before proceeding.
    4. Correct ALL  Controller Area Network (CAN) bus communication concerns (Lost Communication, Implausible, Invalid, No Response, etc.) before proceeding with any Automotive Ethernet diagnosis. The scan tool vehicle topology view only shows CAN bus communication status.
      • Go To  2
  2. ERASE DTCS AND CHECK FOR DTC TO RETURN 
    1. With the scan tool, erase all DTCs.
    2. Turn the ignition off for a minimum of 10.0 seconds.
    3. Turn the ignition on.
    4. Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
      NOTE:

      For this DTC to appear ACTIVE, the Automotive Ethernet ECU must be communicating on a CAN identified by a YELLOW Icon  .

    5. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

  3. PERFORM THE ECU RESET ROUTINE 
    1. With the scan tool, select the Guided Diagnostic tab and reset the Commander first and then the Responder Ethernet ECUs identified in Step 1 of this diagnostic, with this active DTC.
      NOTE:

      For this DTC to appear ACTIVE, the Automotive Ethernet ECU must be communicating on a CAN identified by a YELLOW Icon  .

    2. After the ECU reset procedure is completed for both the Commander and Responder Ethernet ECUs with the scan tool, erase all DTCs.
    3. Turn the ignition off for a minimum of 10.0 seconds.
    4. Turn the ignition on.
    5. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  4

      No 

  4. CHECK FOR POSSIBLE CAUSES 
    NOTE:

    • For intermittent communication issues, or if multiple communication related DTCs are set in other Electronic Control Modules (ECUs), check for loose or poor connections at the suspected ECU power and ground circuits, including at the body sheet-metal mounting areas. When an ECU has multiple power sources and is missing one (Fused B+ or Ignition), the ECU may show on the diagnostic scan tool to be ACTIVE on the CAN bus; and still have an ACTIVE Automotive Ethernet DTC.

    • Performing a load test on the suspected ECU power and ground circuits will help verify that the circuit is able to transfer the amperage needed to perform properly and can confirm that excessive resistance does not exist in the circuit(s) being tested. For additional information on CIRCUIT LOAD TESTING PROCEDURES. Refer to CIRCUIT LOAD TESTING PROCEDURES .

    1. Check the Battery for proper State of Charge (SOC) and the Charging System for proper operation. Refer to: 2.0L - Charging System - DIAGNOSIS AND TESTING and/or 3.6L - Charging System - DIAGNOSIS AND TESTING and/or 5.7L - Charging System - DIAGNOSIS AND TESTING .
    2. With the scan tool, check all Electronic Control Modules (ECUs) for battery and ignition voltage related DTCs and record on the repair order.
    3. Check for and perform all Service Bulletins that could be related to the customer's concern.
    4. Check aftermarket accessories for proper installation. Check for improper electrical connections and fasteners that may be contacting unintended areas.
    5. With the scan tool, check all ECUs for software updates that are related to the customer's concern. Update the ECU(s), as necessary.
    6. Check related wire harnesses for collision related damage.

      Were any problems found?

      Yes 

      • Repair the problem as necessary.
      • With the scan tool, erase DTCs from the related ECUs and perform the appropriate VERIFICATION TEST. If a VERIFICATION TEST is not available for an ECU, perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. DETERMINE THE QUALITY OF ETHERNET COMMUNICATION BETWEEN THE COMMANDER AND RESPONDER ECU 
    1. Using the Mopar Scope, Automotive Ethernet Systems table and wiring diagrams, determine the Automotive Ethernet network circuit integrity between the Commander and Responder ECUs.
      NOTE:

      Some vehicles can have multiple Automotive Ethernet connections within a connector, make sure that you are testing the same Automotive Ethernet for both circuits.

      Connect the black pin for each test lead to Chassis ground. Connect the blue lead to ETHERNET (+) and the red lead to ETHERNET (-) for the circuits to be tested.

      GC0199031Courtesy of CHRYSLER GROUP, LLC
    2. Start the Mopar Scope.
    3. Turn the ignition on.
      NOTE:

      When connected to the vehicle harness correctly, the LEDs on the breakout box will light up to indicate that there is activity on the bus.

    4. A waveform should appear.

      The image below is of a normal ETHERNET bus waveform using the Mopar Scope.

      DESCRIPTION MEASUREMENT
      CHANNEL A 5 volts
      CHANNEL B 5 volts
      TIME BASE 50 μs/div [microseconds / division control]
      ZOOM / VIEW X1 - VERTICAL
      X64 - HORIZONTAL
      NOTE:

      The waveform will show voltage peaks greater than 1.0 volt.

      GC0201377Courtesy of CHRYSLER GROUP, LLC
    5. Compare the known good ethernet waveform from above to the bad ethernet waveforms illustrated below:
      • (+) and (-) Circuit Open - Missing an ECU 
        NOTE:

        The waveform will show voltage peaks less than 1.0 volt.

        GC0201381Courtesy of CHRYSLER GROUP, LLC
        GC0200689Courtesy of CHRYSLER GROUP, LLC
        NOTE:

        Closer comparison between good and bad ethernet waveforms - The voltage peaks on the Bad waveform do NOT reach 1 volt, yet the voltage peaks on the Good waveform will be greater than 1 volt.

      • GC0201728Courtesy of CHRYSLER GROUP, LLC

      Did the Mopar Scope show a bad ethernet waveform?

      Yes 

      • Go To  6

      No 

      • Go To  7
  6. ISOLATE AND CHECK THE FAULTY ETHERNET CIRCUIT(S) FOUND FROM THE BAD WAVEFORM 
    1. Turn the ignition off.
    2. Disconnect the related wire harness connectors of the two ECUs that contain the circuit(s) suspected.
    3. Using a DVOM/DMM, continue to check the integrity of the faulty circuit(s) found from the bad waveform for the Automotive Ethernet system from the Commander to the Responder Ethernet ECUs for the following:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.
      • Circuit Open / High Resistance - less than 1 ohm 
      • Circuit Short To Battery - No voltage  .
      • Circuit Short To Ground - No continuity  .
      • Circuit Short Together - No continuity  .

      Ethernet wiring repairs are not recommended due to the sensitivity of the circuit usage involved. From the above checks, repair / replace  any conditions found as needed.

    4. Reconnect all Automotive Ethernet system harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    5. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    6. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. With the scan tool, select the Guided Diagnostic tab and reset the Commander and Responder Ethernet ECUs identified in Step 1 of this diagnostic, with this active DTC.
      NOTE:

      For this DTC to appear ACTIVE, the Automotive Ethernet ECU must be communicating on a CAN identified by a YELLOW Icon  .

    8. After the ECU reset procedure is completed for both the Commander and Responder Ethernet ECUs with the scan tool, erase all DTCs.
    9. Turn the ignition off for a minimum of 10.0 seconds.
    10. Turn the ignition on.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  7

      No 

  7. REPLACE THE RESPONDER ETHERNET ECU AND RECHECK 
    1. Using the Automotive Ethernet Systems table replace the Responder Ethernet ECU  , in accordance with its Service Information.
    2. With the scan tool, select the Guided Diagnostic tab and reset the Commander and Responder Ethernet ECUs identified in Step 1 of this diagnostic, with this active DTC.
      NOTE:

      For this DTC to appear ACTIVE, the Automotive Ethernet ECU must be communicating on a CAN identified by a YELLOW Icon  .

    3. After the ECU reset procedure is completed for both the Commander and Responder Ethernet ECUs with the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Replace the Commander Automotive Ethernet ECU in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

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