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HOMESERVICE MANUALSTOYOTA2020RAV4 XLE, AWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTCRUISE CONTROL SYSTEMSDYNAMIC RADAR CRUISE CONTROL SYSTEM (EXCEPT HV) - DIAGNOSTIC CODES & CIRCUIT TESTSDYNAMIC RADAR CRUISE CONTROL SYSTEM (FOR GASOLINE MODEL)DTC P1631-81: COMMUNICATION ERROR FROM ECM TO VSC INVALID SERIAL DATA RECEIVED [12/2021 - ]PROCEDURE
2020 Toyota RAV4 XLE, AWD

DTC P1631-81: Communication Error from ECM to VSC Invalid Serial Data Received [12/2021 - ]: Procedure

2020 Toyota RAV4 XLE, AWDSECTION Procedure
  1. CHECK FOR DTCs (ELECTRONICALLY CONTROLLED BRAKE SYSTEM) 
    1. Check for electronically controlled brake system DTCs.

      Refer to DTC CHECK / CLEAR [11/2018 - ]

      Chassis > Brake/EPB > Trouble Codes 

      Result

      Result Proceed to
      Electronically controlled brake system DTCs are not output A
      Electronically controlled brake system DTCs are output B

    Result: 

    B 

    GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ] 

    Result: 

    A 

    See step  2

  2. CHECK FOR DTCs (Radar Cruise1) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2021 - ]

      Powertrain > Radar Cruise1 > Clear DTCs 

    2. Make sure that the DTC detection conditions are met.

      HINT: 

      If the detection conditions are not met, the system cannot detect the malfunction.

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2021 - ]

      Powertrain > Radar Cruise1 > Trouble Codes 

      Result

      Result Proceed to
      DTC P1631-81 is not output A
      DTC P1631-81 is output B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ] 

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [08/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023]  , or refer to  REMOVAL [10/2023 - ] 

RENDER: 1.0x

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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.