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Pinpoint Test V: Abs Module Communication Concern With The HVAC Module

  1. Normal Operation and Fault Conditions 

    With the ignition ON, the HVAC module sends messages to the GWM over the MS-CAN1, the GWM relays the messages to the ABS module over the FD-CAN1. If the ABS module does not receive these messages within a certain time frame (usually less than 1 second), the ABS module sets a DTC. For information on the messages sent to the ABS module by the HVAC module, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    ABS U0164:87 Lost Communication With HVAC Control Module 'A': Missing Message Sets when the ABS module receives "invalid" or "faulted" instead of the actual climate control data.

    Possible Causes 

    • Network communication concern
    • GWM
    • HVAC module

    Visual Inspection and Pre-checks 

    • Make sure the vehicle battery state of charge is at least 80%
    • Make sure the vehicle battery voltage is at least 11 VDC

  2. V1 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE COMMUNICATION

    • Ignition ON.

    • Using a diagnostic scan tool, carry out the HVAC module self-test. Only available in the service information

    Does the HVAC module communicate with the diagnostic scan tool and return DTCs ' 

    Yes  RETRIEVE and RECORD all HVAC module DTCs. REFER to: Climate Control System . If there are no DTCs in the HVAC module, GO to  V3
    No  GO to  V2.

  3. V2 CHECK THE GWM (GATEWAY MODULE A) COMMUNICATION

    • Using a diagnostic scan tool, carry out the GWM self-test. Only available in the service information

    Does the GWM communicate with the diagnostic scan tool and return DTCs ' 

    Yes  RETRIEVE and RECORD all GWMDTCs. REFER to: Controller Area Network (CAN) Module Communications Network .
     
    No  DIAGNOSE the scan tool does not communicate with the GWM. REFER to: Controller Area Network (CAN) Module Communications Network .

  4. V3 RECHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE FOR THE LOST COMMUNICATION DTC (DIAGNOSTIC TROUBLE CODE)

    • Using a diagnostic scan tool, clear the ABS module Diagnostic Trouble Codes (DTCs). Only available in the service information

    • Ignition OFF.

    • Ignition ON.

    • NOTE: When retrieving DTCs, ignore all historical or continuous memory DTCs.

      Using a diagnostic scan tool, carry out the ABS module self-test. Only available in the service information

    Are any of the DTCs listed in the DTC Fault Trigger Conditions table present and active in the ABS module? 

    Yes  GO to  V4.
    No  The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition

  5. V4 REVIEW THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST FOR VOLTAGE-REALTED DTCS

    • Review the results from the ABS module self-test.

    Is DTC U3003:16 or U3003:17 present? 

    Yes  For DTC U3003:16, GO to Pinpoint Test A  For DTC U3003:17, GO to Pinpoint Test F 
    No  GO to  V5.

  6. V5 CHECK FOR GWM (GATEWAY MODULE A) DTCS

    • Using a diagnostic scan tool, carry out the GWM self-test. Only available in the service information

    Are any DTCs present and active in the GWM ' 

    Yes  RETRIEVE and RECORD all GWMDTCs. REFER to: Controller Area Network (CAN) Module Communications Network .
     
    No  GO to  V6.

  7. V6 CHECK FOR HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE DTCS

    • Using a diagnostic scan tool, carry out the HVAC module self-test. Only available in the service information

    Are any DTCs present and active in the HVAC module? 

    Yes  RETRIEVE and RECORD all HVAC module DTCs. REFER to: Climate Control System .
    No  GO to  V7.

  8. V7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

    • NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly 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 module or the 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 of 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  GO to  V8.
    No  The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

  9. V8 CHECK FOR COMMUNICATION DTCS IN OTHER MODULES

    • Ignition ON.

    • NOTE: When retrieving DTCs, ignore all historical or continuous memory DTCs.

      Using a diagnostic scan tool, carry out a Network Test.

    Is any DTC from the Fault Trigger Conditions Table set in 1 or more modules in addition to the ABS module? 

    Yes  GO to  V9.
    No  GO to  V10

  10. V9 VERIFY HVAC (HEATING, VENTILATION AND AIR CONDITIONING) OPERATION

    • Ignition OFF.

    • Disconnect HVAC module C228A.

    • Disconnect GWM C2451.

    • 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 HVAC module C228A Make sure the connector seats and latches correctly.

    • Connect GWM C2451 Make sure the connector seats and latches correctly.

    • Connect ABS Module C135 Make sure the connector seats and latches correctly.

    • Operate the system and verify the concern is still present.

    Is the concern still present? 

    Yes  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 HVAC module. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module .
    No  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.

  11. V10 VERIFY ABS (ANTI-LOCK BRAKE SYSTEM) OPERATION

    • Ignition OFF.

    • Disconnect HVAC module C228A.

    • Disconnect GWM C2451.

    • 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 HVAC module C228A Make sure the connector seats and latches correctly.

    • Connect GWM C2451 Make sure the connector seats and latches correctly.

    • Connect ABS Module C135 Make sure the connector seats and latches correctly.

    • Operate the system and verify the concern is still present.

    Is the concern still present? 

    Yes  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 unit. REFER to: Electric Brake Booster (EBB) .
    No  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.
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