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Pinpoint Test S: U0253:00

WARNING: This page is about a different car, the 2023 Ford Bronco. However, it is still accessible from the selected car via links, so may be relevant.
  1. Refer to MANUAL CLIMATE CONTROL SYSTEM for schematic and connector information.

    Normal Operation and Fault Conditions 

    Control Logic, REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    HVAC U0253:00 Lost Communication With Accessory Protocol Interface Module: No Sub Type Information This DTC sets in the HVAC control module if data messages received from the APIM are missing for more than 5 seconds.

    Possible Sources 

    • Vehicle communication bus
    • APIM
    • HVAC control module

  2. S1 VERIFY THE CUSTOMER CONCERN

    • Ignition ON.

    • Verify there is an observable symptom present.

    Is an observable symptom present? 

    Yes  GO to S2 
    No  CLEAR the DTC. The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  3. S2 CHECK THE COMMUNICATION NETWORK

    • Using a diagnostic scan tool, carry out the network test.

    Does the APIM pass the network test? 

    Yes  GO to S3 
    No  DIAGNOSE the APIM does not communicate with the diagnostic scan tool, REFER to: Controller Area Network (CAN) Module Communications Network .

  4. S3 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE APIM (SYNC MODULE) SELF-TEST

    • Using a diagnostic scan tool, carry out the APIM self-test.

    Are any Diagnostic Trouble Codes (DTCs) recorded? 

    Yes  REFER to: Information and Entertainment System .
    No  GO to S4 

  5. S4 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE (HVAC) HEATING, VENTILATION AND AIR CONDITIONING CONTROL MODULE SELF-TEST

    • Using a diagnostic scan tool, carry out the HVAC control module self-test.

    Is DTC U3003:16 or DTC U3003:17 recorded? 

    Yes  For U3003:16 GO to Pinpoint Test Z  For U3003:17 GO to Pinpoint Test AA 
    No  GO to S5 

  6. S5 RECHECK THE (HVAC) HEATING, VENTILATION AND AIR CONDITIONING CONTROL MODULE DIAGNOSTIC TROUBLE CODES (DTCS)

    NOTE: If new modules were installed prior to the Diagnostic Trouble Code (DTC) being set, the module configuration can be incorrectly set during the Programmable Module Installation (PMI) or the Programmable Module Installation (PMI) may not have been carried out.

    • Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

    • Using a diagnostic scan tool, carry out the HVAC control module self-test.

    Is DTC U0253:00 still present? 

    Yes  GO to S6 
    No  CLEAR the DTC. The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  7. S6 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0253:00 SET IN OTHER MODULES

    • Using a diagnostic scan tool, clear all Diagnostic Trouble Codes (DTCs).

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

    • Using a diagnostic scan tool, retrieve all continuous memory Diagnostic Trouble Codes (DTCs).

    Is DTC U0253:00 set in other modules on the network? 

    Yes  GO to S7 
    No  GO to S8 

  8. S7 CHECK FOR CORRECT APIM (SYNC MODULE) OPERATION

    • Ignition OFF.

    • Disconnect and inspect the APIM electrical connector (if not previously disconnected).

    • Repair:

      • corrosion (install new connector or terminal - clean module pins)
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary

    • Connect APIM electrical connector. Make sure it seats and latches correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable 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 APIM. REFER to: SYNC Module [APIM] .
    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 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE OPERATION

    • Ignition OFF.

    • Disconnect and inspect all HVAC control module electrical connectors (if not previously disconnected).

    • Repair:

      • corrosion (install new connector or terminal - clean module pins)
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary

    • Connect all HVAC control module electrical 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  CHECK OASIS for any applicable 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 HVAC control module. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module .
    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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