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Possible Causes

  1. W1: CHECK THE COMMUNICATION NETWORK 
    • Ignition ON.
    • Using a diagnostic scan tool, carry out the Network Test.
    • Does the HVAC control module pass the Network Test? 
    Yes No
    Go to  W3. Go to  W2.
  2. W2: CHECK THE GATEWAY MODULE (GWM) COMMUNICATION NETWORK 
    • Ignition ON.
    • Using a diagnostic scan tool, carry out the Network Test.

    Does the GWM pass the Network Test? 

    Yes No
    DIAGNOSE the HVAC  control module does not communicate with the diagnostic scan tool. Refer to CONTROLLER AREA NETWORK (CAN) MODULE COMMUNICATIONS NETWORK . DIAGNOSE the GWM  does not communicate with the diagnostic scan tool, Refer to CONTROLLER AREA NETWORK (CAN) MODULE COMMUNICATIONS NETWORK .
  3. W3: CHECK FOR RETURNING ABS (ANTI-LOCK BRAKE SYSTEM) MODULE DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Using a diagnostic scan tool, clear the ABS  module Diagnostic Trouble Codes (DTCs).
    • Ignition OFF.
    • Ignition ON.
    • Using a diagnostic scan tool, carry out the ABS  module self-test.

    Are any of the Diagnostic Trouble Codes (DTCs) in the DTC Fault Trigger Conditions table retrieved again? 

    Yes No
    Go to  W4. The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.
  4. W4: CHECK FOR VOLTAGE-RELATED DIAGNOSTIC TROUBLE CODES (DTCS) IN THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE 
    • Review the recorded Diagnostic Trouble Codes (DTCs) from the ABS  module.

    Is DTC U3003:16 or U3003:17 present in the ABS module? 

    Yes No
    For ABS  module DTC  U3003:16 PINPOINT TESTS A:
    For ABS  module DTC  U3003:17 PINPOINT TESTS F:    		 GO to  W5
  5. W5: CHECK FOR GATEWAY MODULE A (GWM) DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Ignition ON.
    • Using a diagnostic scan tool, carry out the GWM  module self-test.

    Are any GWM Diagnostic Trouble Codes (DTCs) present? 

    Yes No
    DIAGNOSE the GWM  Diagnostic Trouble Codes (DTCs). Refer to CONTROLLER AREA NETWORK (CAN) MODULE COMMUNICATIONS NETWORK . Go to  W6
  6. W6: RETRIEVE ALL HEATING VENTILATION AND AIR CONDITIONING (HVAC) DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Ignition ON.
    • Using a diagnostic scan tool, carry out the HVAC control module self-test.

    Are any HVAC control Diagnostic Trouble Codes (DTCs) present? 

    Yes No
    DIAGNOSE the HVAC  control module Diagnostic Trouble Codes (DTCs). Refer to CLIMATE CONTROL SYSTEM - VEHICLES WITH: DUAL AUTOMATIC TEMPERATURE CONTROL (DATC) , or CLIMATE CONTROL SYSTEM - VEHICLES WITH: ELECTRONIC MANUAL TEMPERATURE CONTROL (EMTC) Go to  W7.
  7. W7: CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN 
    NOTE: If new modules were installed prior to the DTC being set, the module configuration can beincorrectly set during the PMI or the PMI may not have been carried out. 
    • Check the vehicle service history for recent service actions related to the HVAC  or ABS  module. If recent service history is found:
      • Verify the correct replacement module was installed. HVBOM may be used to verify correct part fitment.
      • Verify the configuration or replacement module was correct. re-configure the module using as-built data if prior configuration is suspect.
      • Verify the module was not obtained from a like vehicle and installed into customer vehicle. return the swapped module to source vehicle and obtain new replacement module.
    • Operate the system and determine if the observable symptom is still present.

    Is the observable symptom still present? 

    Yes No
    Go to  W8. The system is operating correctly at this time. The concern may have been due incorrect parts replacement procedures or incorrect module configuration.
  8. W8: CHECK FOR COMMUNICATION DIAGNOSTIC TROUBLE CODES (DTCS) IN OTHER MODULES 
    • Ignition ON.
    • Using a diagnostic scan tool, clear the ABS  module Diagnostic Trouble Codes (DTCs).
    • Using a diagnostic scan tool retrieve all Diagnostic Trouble Codes (DTCs).

    Is DTC U0164:xx or U0424:xx present in one or more modules in addition to the ABS module? 

    Yes No
    Go to  W9 Go to  W10
  9. W9: CHECK FOR CORRECT HEATING VENTILATION AND AIR CONDITIONING (HVAC) MODULE OPERATION 
    • Ignition OFF.
    • Disconnect HVAC  control module C228A .
    • Disconnect GWM  module C2431A
    • Disconnect ABS  module C135
    • Using a good light source, inspect all disconnect electrical connectors for the following:
      • corrosion - install new connector or terminal and clean the module pins
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary.
      • spread terminals - install new terminals as necessary.
    • Connect ABS  module C135 . Make sure it seats and latches correctly.
    • Connect GWM  module C2431A . Make sure it seats and latches correctly.
    • Connect HVAC  control module C228A . Make sure it seats and latches correctly.
    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes No
    CHECK OASIS  for any applicable Technical Service Bulletins (TSBs). If a TSB  exists for this concern, DISCONTINUE this test and FOLLOW the TSB  instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new HVAC  control module. Refer to HEATING, VENTILATION AND AIR CONDITIONING (HVAC) CONTROL MODULE . The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues. Refer to CONNECTOR REPAIR PROCEDURES .
  10. W10: CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION 
    • Ignition OFF.
    • Disconnect HVAC  control module C228A .
    • Disconnect GWM  module C2431A .
    • Disconnect ABS  module C135 .
    • Using a good light source, inspect all disconnected electrical connectors for the following:
      • corrosion - install new connector or terminal and clean the module pins
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary
      • spread terminals - install new terminals as necessary
    • Connect ABS  module C135 . Make sure it seats and latches correctly.
    • Connect GWM  module C2431A . Make sure it seats and latches correctly.
    • Connect HVAC  control module C228A . Make sure it seats and latches correctly.
    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes No
    The HCU and ABS module are a single assembly known as the EBB unit. CHECK OASIS for any service articles: TSB , GSB , SSM or FSA . If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new EBB module. REFER to: ELECTRIC BRAKE BOOSTER (EBB) . The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues. Refer to CONNECTOR REPAIR PROCEDURES .
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