DTC U0424-81: HVAC Control Module to Hybrid Powertrain Control Module Invalid Serial Data Received [11/2015 - ]: Procedure

2018 Toyota Prius Two EcoSECTION Procedure
  1. CHECK DTC OUTPUT (AIR CONDITIONER) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Enter the following menus: Body Electrical / Air Conditioner / Trouble Codes.
    4. Check if DTCs related to the air conditioning system (A/C) are output.

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result  Proceed to
      DTCs related to A/C are not output. A
      DTCs related to A/C are output. B
    5. Turn the power switch off.

    Result: 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2015 - ] 

    Result: 

    GO TO DTC CHART (AIR CONDITIONING SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2015 - 11/2017]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2017 - 12/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2018 - 08/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2019 - 07/2020]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [07/2020 - ] 

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.