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Home >> Ford >> 2018 >> Mustang EcoBoost, 2D Convertible, Standard Trans >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> RCM Guided Routine Testing -- (Pinpoint Tests A - Ax) >> Pinpoint Tests >> PINPOINT TESTs AL: Lost Communication with APIM >> Possible Causes
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Possible Causes

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
NOTE: Only disconnect or reconnect SRS components when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE: Always make sure the correct SRS component is being installed. Parts released for other vehicles may not be compatible even if they appear physically similar. Check the part number listed in the Ford parts catalog to make sure the correct component is being installed. If an incorrect SRS component is installed, DTCs may set.
  1. AL1: VERIFY THE CONCERN 
    WARNING: Before beginning any service procedure in this article, refer to Safety Warnings in General Information article. Failure to follow this instruction may result in serious personal injury. Refer to Pyrotechnic Device Health and Safety Precautions.
    • Ignition ON, engine OFF.
    • Verify there is an observable symptom present.
    • Is an observable symptom present? 
    Yes No
    Go to  AL2. The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.
  2. AL2: CHECK THE COMMUNICATION NETWORK 
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the APIM pass the network test? 
    Yes No
    Go to  AL3. DIAGNOSE the APIM not communicating with the diagnostic scan tool. REFER to Diagnosis and Testing in Module Communications Network article
  3. AL3: CHECK FOR NON-NETWORK RCM DTCS 
    • Carry out the RCM self-test.
    • Are any non-network DTCs present? 
    Yes No
    DIAGNOSE all non-network DTCs first. REFER to the RCM - Restraint Control Module  DTC Chart. The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.
    Go to  AL4.
  4. AL4: CHECK FOR APIM DTCS 
    • Carry out the APIM self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the APIM DTCs. REFER to the appropriate Information and Entertainment System - General Information article Go to  AL5.
  5. AL5: RECHECK FOR DTC U0253:00 
    • Clear the RCM DTCs.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Wait 10 seconds.
    • Carry out the RCM self-test.
    • Is DTC U0253:00 still present? 
    Yes No
    Go to  AL6. The system is operating correctly at this time. The DTC may have set due to high network traffic or an intermittent fault condition.
  6. AL6: 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 APIM and the RCM. If recent service history is found:
      • verify correct replacement module was installed (HVBOM or vehicle parts build list 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 vehicle with concern (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  AL7. The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.
  7. AL7: CHECK FOR CORRECT APIM OPERATION 
    • Ignition OFF.
    • Disconnect and inspect all the APIM and any related in-line connectors.
    • Repair:
      • corrosion (install new connectors or terminals - clean module pins)
      • damaged or bent pins - install new terminals pins
      • pushed-out pins - install new pins as necessary
    • Reconnect the APIM and any related in-line connectors. Make sure they seat and latch correctly.
    • Operate the system and determine if the concern is still present.
    • Is the concern still present? 
    Yes No
    CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new APIM. REFER to the Removal and Installation procedure in the appropriate Information and Entertainment System - General Information article. 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.
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