Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001AR9N
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM (for HV Model): B1798,B1799; Yaw Rate Sensor Module Malfunction; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B1798

Yaw Rate Sensor Module Malfunction

DTC

B1799

Vehicle Stability Control ECU Malfunction

DESCRIPTION

The occupant detection ECU receives signals from the acceleration sensor (airbag ECU assembly) and skid control ECU (brake booster with master cylinder assembly) via CAN communication.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1798

Yaw Rate Sensor Module Malfunction

Acceleration signals are abnormal
  • Acceleration sensor (Airbag ECU assembly)
  • CAN communication system
  • Occupant detection ECU

B1799

Vehicle Stability Control ECU Malfunction

Vehicle speed signal from skid control ECU is abnormal
  • Skid control ECU (Brake booster with master cylinder assembly)
  • CAN communication system
  • Occupant detection ECU

CAUTION / NOTICE / HINT

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

HINT:

  • When DTC B1650 is stored as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1798 or B1799 is output, perform troubleshooting for this DTC first.
  • If it is difficult to perform troubleshooting (wire harness inspection), remove the front passenger seat installation bolts to see under the seat cushion.
  • In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

PROCEDURE

1.

CHECK DTC (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)

(a) Check for electronically controlled brake system DTCs.

Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

OK:

DTCs are not output.

NG

GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM 2019 MY Avalon HV [04/2018 - 08/2019]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART 2020 MY Avalon HV [08/2019 - 08/2020]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART 2021 MY Avalon HV [08/2020 - 08/2021]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART 2022 MY Avalon HV [08/2021 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART

OK

2.

CHECK CAN COMMUNICATION SYSTEM

(a) Using the Techstream, check if the CAN communication system is functioning normally.

OK:

CAN communication system is functioning normally.

HINT:

Refer to Communication Bus Check in CAN Communication System.

Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): DIAGNOSIS SYSTEM 2021 MY Avalon HV [08/2020 - 08/2021]; NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): DIAGNOSIS SYSTEM 2022 MY Avalon HV [08/2021 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): DIAGNOSIS SYSTEM

NG

GO TO CAN COMMUNICATION SYSTEM

OK

3.

CHECK DTC (HEALTH CHECK)

(a) Turn the power switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG) and turn the Techstream on.

(d) Enter the following menus: System Select / Health Check.

OK:

DTCs are not output.

OK

USE SIMULATION METHOD TO CHECK

NG

GO TO OTHER DIAGNOSTIC TROUBLE CODE CHART