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Inspection and Verification

  1. Verify the customer concern.
  2. Visually inspect the following for obvious signs of electrical damage.
    VISUAL INSPECTION CHART

    Electrical
    • Battery junction box (BJB) fuse(s):
      • 18 (40A) (no communication with smart junction box [SJB])
      • 15 (15A) (no communication with transmission control module [TCM])
      • 32 (30A) (no communication with driver seat module [DSM])
      • 48 (10A) (no communication with TCM)
      • 49 (15A) (no communication with powertrain control module [PCM])
    • SJB fuse(s):
      • 7 (7.5A) (no communication with electronic automatic temperature control (EATC) module, SJB, PCM, instrument cluster)
      • 9 (20A) (no power to scan tool)
      • 10 (7.5A) (no communication with DSM, satellite radio receiver)
      • 11 (20A) (no communication with audio unit, DVD player)
      • 15 (10A) (no communication with audio unit)
      • 19 (10A) (no communication with differential electronic module (DEM), anti-lock brake system (ABS) module, parking aid module)
      • 20 (7.5A) (no communication with EATC module, instrument cluster)
      • 21 (7.5A) (no communication with restraints control module [RCM])
      • 23 (7.5A) (no communication with instrument cluster)
    • Data link connector (DLC)
    • Wiring harness
    • Circuitry
  3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
    4. NOTE: Make sure to use the latest scan tool software release.
    NOTE: The vehicle communication module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.
  4. If the cause is not visually evident, connect the scan tool to the DLC.

    If the scan tool does not communicate with the VCM: 

    • Check the VCM connection to the vehicle.
    • Check the scan tool connection to the VCM.
    • Go to Pinpoint Test P , to diagnose no power to the scan tool.
    5. NOTE: During the network test, the scan tool will first attempt to communicate with the PCM, after establishing communication with the PCM, the scan tool will then attempt to communicate with all other modules on the vehicle.
  5. Carry out the network test:
    • If the network test passes, retrieve and record the continuous memory DTCs and proceed to Step 6.
    • If the network test fails, go to Symptom Chart  to identify the module not communicating.
  6. If the DTCs retrieved are related to the concern, go to the Communication Network Diagnostic Trouble Code (DTC) Index. For all other DTCs, refer to MULTIFUNCTION ELECTRONIC MODULES article.
  7. If no DTCs related to the concern are retrieved, go to Symptom Chart .
NOTE: DTC U1900 will set in a module that is reporting a communication fault from another module on the data bus. The module that reports the fault is not the problem module.
COMMUNICATION NETWORK DIAGNOSTIC TROUBLE CODES (DTC) INDEX

DTC Description Source Action
U0001 High Speed CAN Communication Bus Off Differential electronic module (DEM) DTC U0001 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0001 High Speed CAN Communication Bus Off TCM - CVT transmission DTC U0001 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0002 High Speed CAN Communication Bus Performance Instrument cluster DTC U0002 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0020 Low Speed CAN Communication Bus Performance Instrument cluster DTC U0020 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Anti-lock brake system (ABS) module DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Audio unit DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Digital versatile disc (DVD) player DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Electronic automatic temperature control (EATC) module DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Restraints control module (RCM) DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off Smart junction box (SJB) DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0073 Control Module Communication Bus Off TCM - CVT transmission DTC U0073 indicates the module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with the scan tool.
U0100 Lost Communication With ECM/PCM TCM - Aisin transmission CLEAR the DTC. REPEAT the network test with the scan tool. FOLLOW the appropriate pinpoint test for the module which fails the network test.
U0100 Lost Communication With ECM/PCM TCM - CVT transmission CLEAR the DTC. REPEAT the network test with the scan tool. FOLLOW the appropriate pinpoint test for the module which fails the network test.
U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module DEM CLEAR the DTC. REPEAT the network test with the scan tool. FOLLOW the appropriate pinpoint test for the module which fails the network test.
U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module TCM - Aisin transmission CLEAR the DTC. REPEAT the network test with the scan tool. FOLLOW the appropriate pinpoint test for the module which fails the network test.
U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module TCM - CVT transmission CLEAR the DTC. REPEAT the network test with the scan tool. FOLLOW the appropriate pinpoint test for the module which fails the network test.
U0415 Invalid Data Received From Anti-Lock Brake System Control Module TCM - CVT transmission RETRIEVE and FOLLOW non-network DTCs from the ABS module. REFER to VEHICLE DYNAMIC SYSTEMS article.
U0415 Invalid Data Received From Anti-Lock Brake System Control Module TCM - Aisin transmission RETRIEVE and FOLLOW non-network DTCs from the ABS module. REFER to VEHICLE DYNAMIC SYSTEMS article.
U1900 CAN Communication Bus Fault-Receive Error ABS module Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error Audio unit Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error DSM Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error DVD player Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error Instrument cluster Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error RCM Go to Symptom Chart  for module that failed the network test.
U1900 CAN Communication Bus Fault-Receive Error SJB Go to Symptom Chart  for module that failed the network test.
U1901 CAN Network #2 Communication Bus Fault - Receive Error Instrument cluster Go to Symptom Chart  for module that failed the network test.
U2023 Fault Received From External Node ABS module RETRIEVE and FOLLOW non-network DTCs from other modules. REFER to MULTIFUNCTION ELECTRONIC MODULES article.
U2023 Fault Received From External Node Instrument cluster RETRIEVE and FOLLOW non-network DTCs from other modules. REFER to MULTIFUNCTION ELECTRONIC MODULES article.
U2023 Fault Received From External Node RCM RETRIEVE and FOLLOW non-network DTCs from other modules. REFER to MULTIFUNCTION ELECTRONIC MODULES article.
U2026 Family Entertainment System Not Responding Audio unit Go to Pinpoint Test K .
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