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HOMESERVICE MANUALSFORD2018EXPEDITION MAX LIMITED, 4WDREPAIR AND DIAGNOSISBRAKESBRAKES CONTROL SYSTEMSABS GUIDED ROUTINE TESTINGPINPOINT TESTSPINPOINT TESTS BH: ABS MODULE COMMUNICATION CONCERN WITH THE RCMPOSSIBLE CAUSES
2018 Ford Expedition MAX Limited, 4WD

Possible Causes

2018 Ford Expedition MAX Limited, 4WDSECTION Possible Causes
  • Network communication concern
  • RCM
  • ABS module
  1. BH1: 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 RCM pass the network test? 
      Yes No
      Go to  BH2. DIAGNOSE the no communication with the RCM. Refer to Module Communications Network article.
  2. BH2: RECHECK FOR THE ABS MODULE DTCS 
    • Clear the ABS DTCs.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Carry out the ABS self-test.
    • Record all ABS module DTCs.
    • Is any DTC from the DTC Fault Trigger Conditions table retrieved again? 
      Yes No
      Go to  BH3. The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.
  3. BH3: CHECK FOR VOLTAGE DTCS IN THE ABS MODULE 
    • Review the recorded DTCs from the ABS module self-test.
    • Is DTC U3003:16 or U3003:17 present? 
      Yes No
      For DTC U3003:17, Go to PINPOINT TEST F .
      For DTC U3003:16, Go to PINPOINT TEST A .      		 Go to  BH4.
  4. BH4: CHECK FOR DTCS IN THE RCM 
    • Carry out the RCM self-test.
    • Record all DTCs from the RCM self-test.
    • Are any DTCs present? 
      Yes No
      DIAGNOSE the RCM DTCs. REFER to the Supplemental Restraint System article. Go to  BH5.
  5. BH5: 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 RCM 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 No
      Go to  BH6. The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.
  6. BH6: CHECK FOR LOST COMMUNICATION DTCS SET IN OTHER MODULES 
    • Retrieve the continuous memory DTCs.
    • Is DTC U0151xx or U0452:xx set in 1 or more modules in addition to the ABS module? 
      Yes No
      Go to  BH10. Go to  BH11.
  7. BH7: CHECK THE PRIVATE HS-CAN FOR A SHORT TO GROUND 
    WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
    • Ignition OFF.
    • Wait one minute.
    • ABS Module connector disconnected. (C135)
    • RCM_A connector disconnected. (C310A)
    • RCM_B connector disconnected. (C310B)
    • Measure the resistance between:
      (+) RCM_B (C310B) Connector, Harness Side (-)
      CAN- Ground
      CAN+ Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      Go to  BH8. REPAIR the circuit.
  8. BH8: CHECK THE PRIVATE HS-CAN FOR AN OPEN 
    • Measure the resistance between:
      (+) RCM_B (C310B) Connector, Harness Side (-) ABS Module (C135) Connector, Harness Side
      CAN- CAN-
      CAN+ CAN+
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  BH9. REPAIR the circuit.
  9. BH9: CHECK THE PRIVATE HS-CAN FOR A SHORT TOGETHER 
    • Measure the resistance between:
      (+) RCM_B (C310B) Connector, Harness Side (-) RCM_B (C310B) Connector, Harness Side
      CAN- CAN+
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      Go to  BH11. REPAIR the circuit.
  10. BH10: CHECK FOR CORRECT RCM OPERATION 
    WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.