Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001BKCJ
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 -           ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for Gasoline Model): B1825-B1828; Short in Side Squib (LH) Circuit; 2019 - 2022 MY Avalon [04/2018 -        ]

DTC

B1825

Short in Side Squib (LH) Circuit

DTC

B1826

Open in Side Squib (LH) Circuit

DTC

B1827

Short in Side Squib (LH) Circuit (to Ground)

DTC

B1828

Short in Side Squib (LH) Circuit (to +B)

DESCRIPTION

The front side squib LH circuit consists of the airbag ECU assembly and front seat airbag assembly LH.

The airbag ECU assembly uses this circuit to deploy the airbag when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the front side squib LH circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Test Mode / Check Mode

B1825

Short in Side Squib (LH) Circuit
  • The airbag ECU assembly detects a line short in the front side squib LH circuit during the primary check.
  • Front side squib LH malfunction
  • Airbag ECU assembly malfunction
  • Floor wire
  • Front side squib LH (Front seat airbag assembly LH)
  • Airbag ECU assembly

Comes on

Applies to check mode

B1826

Open in Side Squib (LH) Circuit
  • The airbag ECU assembly detects an open in the front side squib LH circuit.
  • Front side squib LH malfunction
  • Airbag ECU assembly malfunction
  • Floor wire
  • Front side squib LH (Front seat airbag assembly LH)
  • Airbag ECU assembly

Comes on

Applies to check mode

B1827

Short in Side Squib (LH) Circuit (to Ground)
  • The airbag ECU assembly detects a short to ground in the front side squib LH circuit.
  • Front side squib LH malfunction
  • Airbag ECU assembly malfunction
  • Floor wire
  • Front side squib LH (Front seat airbag assembly LH)
  • Airbag ECU assembly

Comes on

Applies to check mode

B1828

Short in Side Squib (LH) Circuit (to +B)
  • The airbag ECU assembly detects a short to B+ in the front side squib LH circuit.
  • Front side squib LH malfunction
  • Airbag ECU assembly malfunction
  • Floor wire
  • Front side squib LH (Front seat airbag assembly LH)
  • Airbag ECU assembly

Comes on

Applies to check mode

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

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

HINT:

  • Perform the simulation method by selecting check mode (Signal Check) using the Techstream.

    Click here 2019 - 2022 MY Avalon [04/2018 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for Gasoline Model): CHECK MODE PROCEDURE

  • After selecting check mode (Signal Check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city road or rough road.

    Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

CHECK CONNECTORS

(a) Turn the engine switch off.

*1

Front Seat Airbag Assembly LH

*2

Airbag ECU Assembly

*3

Floor Wire

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connectors are properly connected to the front seat airbag assembly LH and airbag ECU assembly.

OK:

The connectors are properly connected.

HINT:

If the connectors are not properly connected, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the front seat airbag assembly LH and airbag ECU assembly.

(e) Check that the terminals of the connectors are not deformed or damaged.

OK:

The terminals are not deformed or damaged.

(f) Check that the short springs of the activation prevention mechanism of the floor wire connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

NG

REPLACE FLOOR WIRE
OK

2.

CHECK FRONT SEAT AIRBAG ASSEMBLY LH

(a) Connect the connector to the airbag ECU assembly.

*1

Front Seat Airbag Assembly LH

*2

Airbag ECU Assembly

*a

Front view of wire harness connector

(to Front Seat Airbag Assembly LH)

(b) Connect SST (resistance 2.1 Ω) to connector C.

CAUTION:

Never connect a tester to the front seat airbag assembly LH for measurement, as this may lead to a serious injury due to airbag deployment.

NOTICE:

  • Do not forcibly insert SST into the terminals of the connector when connecting it.
  • Insert SST straight into the terminals of the connector.

SST: 09843-18061

(c) Connect the cable to the negative (-) battery terminal.

(d) Turn the engine switch on (IG), and wait for at least 60 seconds.

(e) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the engine switch off.

(g) Turn the engine switch on (IG), and wait for at least 60 seconds.

(h) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1825, B1826, B1827 or B1828 is not output.

HINT:

Codes other than DTCs B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.

(i) Turn the engine switch off.

(j) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(k) Disconnect SST from connector C.

OK

REPLACE FRONT SEAT AIRBAG ASSEMBLY LH 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; SUPPLEMENTAL RESTRAINT SYSTEMS: FRONT SEAT SIDE AIRBAG ASSEMBLY: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: FRONT SEAT SIDE AIRBAG ASSEMBLY: REMOVAL

NG

3.

CHECK FLOOR WIRE

(a) Disconnect the floor wire from the airbag ECU assembly.

*1

Front Seat Airbag Assembly LH

*2

Airbag ECU Assembly

*3

Floor Wire

*a

Front view of wire harness connector

(to Front Seat Airbag Assembly LH)

(b) Check for a short to B+ in the circuit.

(1) Connect the cable to the negative (-) battery terminal.

(2) Turn the engine switch on (IG).

(3) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

K43-1 (SFL+) - Body ground

Engine switch on (IG)

Below 1 V

K43-2 (SFL-) - Body ground

Engine switch on (IG)

Below 1 V

(4) Turn the engine switch off.

(5) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check for an open in the circuit.

(1) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

K43-1 (SFL+) - K43-2 (SFL-)

Always

Below 1 Ω

(d) Check for a short to ground in the circuit.

(1) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

K43-1 (SFL+) - Body ground

Always

1 MΩ or higher

K43-2 (SFL-) - Body ground

Always

1 MΩ or higher

(e) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector B.

Click here 2019 - 2022 MY Avalon [04/2018 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for Gasoline Model): SYSTEM DESCRIPTION

(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

K43-1 (SFL+) - K43-2 (SFL-)

Always

1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector B to the original condition.

NG

REPLACE FLOOR WIRE
OK

4.

CHECK DTC

(a) Connect the connectors to the front seat airbag assembly LH and airbag ECU assembly.

*1

Front Seat Airbag Assembly LH

*2

Airbag ECU Assembly

(b) Connect the cable to the negative (-) battery terminal.

(c) Turn the engine switch on (IG), and wait for at least 60 seconds.

(d) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the engine switch off.

(f) Turn the engine switch on (IG), and wait for at least 60 seconds.

(g) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1825, B1826, B1827 or B1828 is not output.

HINT:

Codes other than DTCs B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE AIRBAG ECU ASSEMBLY 2019 - 2020 MY Avalon Avalon HV [04/2018 - 08/2020]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL 2021 MY Avalon Avalon HV [08/2020 - 08/2021]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL