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Home >> Lincoln >> 2018 >> Navigator Select, 4WD >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> RCM Guided Routine Testing -- (2 Of 4) >> Pinpoint Tests >> Pinpoint Test AHA: Lost Communication with PCM (No OCS) >> Possible Causes

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. AHA1: 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.
    • Connect the diagnostic scan tool.
    • Check that a vehicle session can be established using the diagnostic scan tool.
    • Is a vehicle session established? 
      Yes No
      Go to  AHA2. To diagnose no communication with the PCM, REFER to: Module Communications Network article
  2. AHA2: VERIFY THE SCAN TOOL COMMUNICATES WITH THE PCM 
    • Carry out the RCM self-test.
    • Clear the RCM DTCs.
    • Wait 10 seconds.
    • Carry out the RCM self-test.
    • Is DTC U0100:00 retrieved again? 
      Yes No
      Go to  AHA3. 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. AHA3: CHECK FOR NON-NETWORK RCM/OCSM DTCS 
    • Carry out the PCM KOEO self-test.
    • Check for recorded DTCs from the PCM KOEO self-test.
    • Is DTC P0562 or P0563 recorded? 
      Yes No
      DIAGNOSE the PCM Diagnostic Trouble Codes (DTCs). Refer to the appropriate article for the procedure. Go to  AHA4.
  4. AHA4: CHECK FOR PCM DTCS 
    • Carry out the RCM self-test.
    • Check for recorded DTCs from the RCM self-test.
    • Is DTC U3003:16 or U3003:17 recorded? 
      Yes No
      GO to PINPOINT TEST ANA . Go to  AHA5.
  5. AHA5: CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN 
    • Using a diagnostic scan tool, perform self-test for all modules.
    • Is DTC U0100:00 set in the ABS module or BCM? 
      Yes No
      CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new PCM. Refer to the appropriate article for the procedure. CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new RCM. REFER to: Supplemental Restraint System article
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