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Pinpoint Test S: Abs Module Communication Concern With The GWM

  1. Refer to Module Communications Network for schematic and connector information.

    Normal Operation and Fault Conditions 

    REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .

    With the ignition ON, the GWM sends messages to the ABS module over the FD-CAN. If the ABS module does not receive these messages within a certain time frame (usually less than 1 second), the ABS module sets Diagnostic Trouble Codes (DTCs). This can be due to a GWM failure, a circuit failure on the CAN or an excessive load on the network.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    ABS U0146:87 Lost Communication With Serial Data Gateway 'A': Missing Message This DTC sets in the ABS module if the messages from the GWM are missing for more than 5 seconds.

    Possible Causes 

    • Network communication concern
    • GWM

    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. S1 CHECK THE GWM (GATEWAY MODULE A) COMMUNICATION

    • Ignition ON.

    • 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. If there are no DTCs in the GWM, GO to  S2.
    No  DIAGNOSE the scan tool does not communicate with the GWM. REFER to: Controller Area Network (CAN) Module Communications Network .

  3. S2 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  S3.
    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

  4. S3 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  S4

  5. S4 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  S5.

  6. S5 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 GWM 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  S6.
    No  The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

  7. S6 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  S7.
    No  GO to  S8

  8. S7 VERIFY GWM (GATEWAY MODULE A) OPERATION

    • Ignition OFF.

    • 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 GWM C2431A 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 GWM. REFER to: Gateway Module A (GWM) .
    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.

  9. S8 VERIFY ABS (ANTI-LOCK BRAKE SYSTEM) OPERATION

    • Ignition OFF.

    • 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 GWM C2431A 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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