SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B1825-B1828; Short in Side Squib (LH) Circuit; 2019 - 2022 MY Avalon HV [04/2018

Last Modified: 08-21-2023	6.11:8.1.0	Doc ID: RM100000001AR8T
Model Year Start: 2019	Model: Avalon HV	Prod Date Range: [04/2018 - ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B1825-B1828; Short in Side Squib (LH) Circuit; 2019 - 2022 MY Avalon HV [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 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

HINT:

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

PROCEDURE

1.	CHECK CONNECTORS

(a) Turn the power switch off.

*1	Front Seat Airbag Assembly LH
*2	Airbag ECU Assembly
*3	Floor Wire

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

CAUTION:

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

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.

REPLACE FLOOR WIRE

2.	CHECK FRONT SEAT AIRBAG ASSEMBLY LH

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

Front Seat Airbag Assembly LH

Airbag ECU Assembly

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

(d) Turn the power 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 power switch off.

(g) Turn the power 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 power switch off.

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

CAUTION:

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

(k) Disconnect SST from connector C.

REPLACE FRONT SEAT AIRBAG ASSEMBLY LH

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 (-) auxiliary battery terminal.

(2) Turn the power 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	Power switch on (IG)	Below 1 V
K43-2 (SFL-) - Body ground	Power switch on (IG)	Below 1 V

(4) Turn the power switch off.

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

CAUTION:

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

(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

(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.

REPLACE FLOOR WIRE

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 (-) auxiliary battery terminal.

(d) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the power switch off.

(f) Turn the power 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.

USE SIMULATION METHOD TO CHECK

REPLACE AIRBAG ECU ASSEMBLY