LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2021 >> Edge ST-Line, FWD >> Repair and Diagnosis >> Brakes >> Brakes Control Systems >> Abs Guided Routine - Pinpoint Tests C - F >> Pinpoint Tests DA: SASM Communication Concern With Auxiliary Heater Control Module >> Possible Causes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Possible Causes

  1. DA1: CHECK THE COMMUNICATION NETWORK 
    • Ignition ON, engine OFF.
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the AHCM pass the network test? 
    Yes No
    Go to  DA2. DIAGNOSE the AHCM does not communicate with the diagnostic scan tool. REFER to Module Communications Network article.
  2. DA2: CHECK THE GWM COMMUNICATION 
    • Ignition ON, engine OFF.
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the GWM pass the network test? 
    Yes No
    Go to  DA3. DIAGNOSE the GWM does not communicate with the diagnostic scan tool. REFER to Module Communications Network article.
  3. DA3: RECHECK FOR THE SASM DTCS 

    Carry out the SASM self-test.

    • Clear the SASM DTCs.
    • Put the ABS module in sleep mode by performing the following steps:
      • With ALL doors closed, set the ignition from ON to OFF.
      • Disconnect the diagnostic scan tool.
      • Open the door, exit the vehicle and close the door.
      • Wait a minimum of 90 seconds for the ABS module to enter sleep mode.
    • Ignition ON, engine OFF.

    Carry out the SASM self-test.

    • Record the SASM DTCs.
    • Is DTC U0425:xx retrieved again? 
    Yes No
    Go to  DA4. 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. DA4: CHECK FOR VOLTAGE DTCS IN THE SASM 
    • Review the recorded DTCs from the SASM self-test.
    • Is DTC U3003:17 or U3003:1C present? 
    Yes No
    For DTC U3003:17, GO to PINPOINT TEST BE.
    For DTC U3003:1C, GO to PINPOINT TEST BD.    		 Go to  DA5.
  5. DA5: RETRIEVE ALL DTCS FROM THE GWM 

    Carry out the GWM self-test.

    • Record the DTCs from the GWM self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the GWM DTCs. REFER to Module Communications Network article. Go to  DA6.
  6. DA6: RETRIEVE ALL DTCS FROM THE AHCM 
    • Using a diagnostic scan tool, carry out the AHCM self-test.
    • Record the DTCs from the AHCM self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the AHCM DTCs. REFER to Climate Control System - General Information (1 Of 2) - F450 - F600 Super Duty and/or Climate Control System - General Information (2 Of 2) - F450 - F600 Super Duty article. Go to  DA7.
  7. DA7: 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 AHCM or the SASM. 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 No
    Go to  DA8. The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.
  8. DA8: CHECK FOR COMMUNICATION DTCS IN OTHER MODULES 
    • Ignition ON, engine OFF.
    • Retrieve the continuous memory DTCs.
    • Is DTC U0425:xx set in 1 or more modules in addition to the SASM? 
    Yes No
    Go to  DA9. Go to  DA10.
  9. DA9: VERIFY AHCM OPERATION 
    • Ignition OFF.
    • Disconnect all AHCM electrical connectors.
    • Disconnect all SASM electrical connectors.
    • 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 all SASM electrical connectors. Make sure they seat and latch correctly.
    • Connect all AHCM electrical connectors. Make sure they seat and latch correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    Yes No
    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 services articles address this concern, INSTALL a new AHCM. REFER to Climate Control System - General Information (1 Of 2) - F450 - F600 Super Duty and/or Climate Control System - General Information (2 Of 2) - F450 - F600 Super Duty article.    		 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.
  10. DA10: VERIFY SASM OPERATION 
    • Ignition OFF.
    • Disconnect all AHCM electrical connectors.
    • Disconnect all SASM electrical connectors.
    • 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 all AHCM electrical connectors. Make sure they seat and latch correctly.
    • Connect all SASM electrical connectors. Make sure they seat and latch correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    Yes No
    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 services articles address this concern, INSTALL a new SASM-clockspring assembly. REFER to Supplemental Restraint System article.    		 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.
scientia non olet · About LEMON Manuals