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Pinpoint Test Ax : U0164

  1. NOTE: The Inverter System Controller (ISC) is referred to as the SOBDMC (Secondary On-Board Diagnostic Control Module C) in the scan tool.

    Normal Operation and Fault Conditions 

    REFER to: Electric Powertrain Control - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    SOBDMC U0164:00 Lost Communication With HVAC Control Module: No Sub Type Information This DTC sets when messages are missing from the HVAC module.

    Possible Sources 

    • Communications network concern
    • HVAC module.

  2. AX1 VERIFY THE CONCERN

    • Ignition ON.

    • Verify there is an observable symptom present.

    Is an observable symptom present? 

    Yes  GO to  AX2
    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. AX2 VERIFY THE DIAGNOSTIC SCAN TOOL COMMUNICATES WITH THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE

    • Connect the diagnostic scan tool to the vehicle.

    • Attempt to establish a vehicle session using the diagnostic scan tool.

    Can a vehicle session be established? 

    Yes  GO to  AX3
    No  REFER to: Communications Network .

  4. AX3 CHECK FOR NON-NETWORK DIAGNOSTIC TROUBLE CODES (DTCS)

    • Using a diagnostic scan tool, carry out the Inverter System Controller (ISC) self-test.

    Are any non-network DTCs present? 

    Yes  DIAGNOSE all non-network DTCs first. REFER to Diagnostic Trouble Code (DTC) Chart .
    No  GO to  AX4

  5. AX4 CHECK FOR NON-NETWORK HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE DIAGNOSTIC TROUBLE CODES (DTCS)

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

    Are any non-network DTCs present? 

    Yes  REFER to: Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC)/Electronic Automatic Temperature Control (EATC) .
    No  GO to  AX5

  6. AX5 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) AND HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE CALIBRATION LEVELS

    • Verify the Inverter System Controller (ISC) and the HVAC module are at the latest calibration levels.

    Are the Inverter System Controller (ISC) and the HVAC module at the latest calibration levels? 

    Yes  GO to  AX6
    No  UPDATE the Inverter System Controller (ISC) or HVAC module to the latest calibration level.

  7. AX6 RECHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0164

    • Using a diagnostic scan tool, clear the Inverter System Controller (ISC) DTCs.

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

    • Using a diagnostic scan tool, carry out the self-test for the Inverter System Controller (ISC).

    Is DTC U0164 present? 

    Yes  GO to  AX7
    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.

  8. AX7 CHECK FOR OTHER CAUSES OF NETWORK COMMUNICATION 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 HVAC module and the Inverter System Controller (ISC). 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  AX8
    No  The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

  9. AX8 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE OPERATION

    • Ignition OFF.

    • Disconnect and inspect the HVAC module 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 HVAC module 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, REFER to: Communications Network .
    No  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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