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Pinpoint Test P: U0140:00

  1. Refer to MANUAL CLIMATE CONTROL SYSTEM for schematic and connector information.

    Normal Operation and Fault Conditions 

    The HVAC control module communicates with the BCM over the CAN. If messages are missing or not received from the BCM, the climate control system may not operate not operate correctly. REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - System Operation and Component Description

    Inspect for loose or corroded BCM and HVAC control module connections.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    HVAC U0140:00 Lost Communication With Body Control Module: No Sub Type Information Sets in continuous memory when the HVAC control module detects network messages are missing from the BCM for more than 5 seconds.

    Possible Sources 

    • Network communication concern
    • Wiring, terminals or connectors
    • Over or undervoltage concerns
    • HVAC control module
    • BCM

  2. P1 VERIFY THE CONCERN

    • Ignition ON.

    • Verify there is an observable symptom present.

    Is an observable symptom present? 

    Yes  GO to  P2
    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.

  3. P2 CHECK THE NETWORK COMMUNICATION

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

    Does the BCM pass the network test? 

    Yes  GO to  P3
    No  REFER to: Controller Area Network (CAN) Module Communications Network

  4. P3 CHECK FOR NON-NETWORK DIAGNOSTIC TROUBLE CODES (DTCS)

    • Using a diagnostic scan tool, carry out the self-test for the module in question (HVAC control module) setting the DTC.

    Are any non-network Diagnostic Trouble Codes (DTCs) present? 

    Yes  DIAGNOSE all non-network Diagnostic Trouble Codes (DTCs) first. REFER to the appropriate Diagnostic Trouble Code (DTC) Chart .
    No  GO to  P4

  5. P4 CHECK FOR NON-NETWORK BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

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

    Are any non-network Diagnostic Trouble Codes (DTCs) present? 

    Yes  REFER to: Body Control Module (BCM)
    No  GO to  P5

  6. P5 RECHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0140:00

    • Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs) for the module in question [HVAC control module] setting the DTC.

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

    • Using a diagnostic scan tool, carry out the self-test for the module in question [HVAC control module] setting the DTC.

    Is DTC U0140:00 still present? 

    Yes  GO to  P6
    No  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. P6 CHECK FOR OTHER CAUSES OF NETWORK COMMUNICATION CONCERN

    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.

    • Check the vehicle service history for recent service actions related to the BCM and the module in question [ HVAC control module] setting the DTC. If recent service history is found:

      • verify correct replacement module was installed

        • vehicle parts build list may be used to verify correct part fitment

      • verify the configuration of replacement module was correct

        • re-configure 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  GO to  P7
    No  The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

  8. P7 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

    • Ignition OFF.

    • Disconnect and inspect all BCM 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 BCM 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 BCM. REFER to: Body Control Module (BCM)
    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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