SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B181A-B181D; Short in Passenger Side Airbag Variable Vent Hole Squib Circuit; 2020 - 2022 MY Corolla Corolla HV [01/2019

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001G4Q4
Model Year Start: 2020	Model: Corolla	Prod Date Range: [01/2019 - 09/2022]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B181A-B181D; Short in Passenger Side Airbag Variable Vent Hole Squib Circuit; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

DTC

B181A

Short in Passenger Side Airbag Variable Vent Hole Squib Circuit

DTC

B181B

Open in Passenger Side Airbag Variable Vent Hole Squib Circuit

DTC

B181C

Short to GND in Passenger Side Airbag Variable Vent Hole Squib Circuit

DTC

B181D

Short to B+ in Passenger Side Airbag Variable Vent Hole Squib Circuit

DESCRIPTION

The passenger side airbag variable vent hole squib circuit consists of the airbag sensor assembly and instrument panel passenger airbag assembly.

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

These DTCs are stored when a malfunction is detected in the passenger side airbag variable vent hole squib circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Test Mode / Check Mode
B181A	Short in Passenger Side Airbag Variable Vent Hole Squib Circuit	The airbag sensor assembly detects a line short in the passenger side airbag variable vent hole squib circuit during the primary check. Passenger side airbag variable vent hole squib malfunction Airbag sensor assembly malfunction	Instrument panel wire No. 2 instrument panel wire Passenger side airbag variable vent hole squib (Instrument panel passenger airbag assembly) Airbag sensor assembly	Comes on	Applies to check mode
B181B	Open in Passenger Side Airbag Variable Vent Hole Squib Circuit	The airbag sensor assembly detects an open in the passenger side airbag variable vent hole squib circuit. Passenger side airbag variable vent hole squib malfunction Airbag sensor assembly malfunction	Instrument panel wire No. 2 instrument panel wire Passenger side airbag variable vent hole squib (Instrument panel passenger airbag assembly) Airbag sensor assembly	Comes on	Applies to check mode
B181C	Short to GND in Passenger Side Airbag Variable Vent Hole Squib Circuit	The airbag sensor assembly detects a short to ground in the passenger side airbag variable vent hole squib circuit. Passenger side airbag variable vent hole squib malfunction Airbag sensor assembly malfunction	Instrument panel wire No. 2 instrument panel wire Passenger side airbag variable vent hole squib (Instrument panel passenger airbag assembly) Airbag sensor assembly	Comes on	Applies to check mode
B181D	Short to B+ in Passenger Side Airbag Variable Vent Hole Squib Circuit	The airbag sensor assembly detects a short to B+ in the passenger side airbag variable vent hole squib circuit. Passenger side airbag variable vent hole squib malfunction Airbag sensor assembly malfunction	Instrument panel wire No. 2 instrument panel wire Passenger side airbag variable vent hole squib (Instrument panel passenger airbag assembly) Airbag sensor 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	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor Assembly
*3	No. 2 Instrument Panel Wire
*4	Instrument Panel 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.

(c) Check that the connectors are properly connected to the instrument panel passenger airbag assembly and airbag sensor assembly. Also check that the connectors that link the instrument panel wire and No. 2 instrument panel wire are properly connected.

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 instrument panel passenger airbag assembly and airbag sensor assembly. Also disconnect the instrument panel wire from the No. 2 instrument panel wire.

(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 No. 2 instrument panel wire connector (on the instrument panel passenger airbag assembly side) is not loose, deformed or damaged.

OK:

The airbag connector locking button is not disengaged, and the claw of the lock is not deformed or damaged.

(g) Check that the short springs of the activation prevention mechanisms of the instrument panel wire connector and No. 2 instrument panel wire connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

REPLACE WIRE HARNESS

2.	CHECK INSTRUMENT PANEL PASSENGER AIRBAG ASSEMBLY

(a) Connect the instrument panel wire to the No. 2 instrument panel wire and airbag sensor assembly.

*1	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor Assembly
*a	Front view of wire harness connector (to Instrument Panel Passenger Airbag Assembly)
*b	Color: Green

(b) Connect SST (resistance 2.1 Ω) to connector E (green connector).

CAUTION:

Never connect a tester to the instrument panel passenger airbag assembly 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 B181A, B181B, B181C or B181D is not output.

HINT:

Codes other than DTCs B181A, B181B, B181C and B181D 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 E.

REPLACE INSTRUMENT PANEL PASSENGER AIRBAG ASSEMBLY

3.	CHECK PASSENGER SIDE AIRBAG VARIABLE VENT HOLE SQUIB CIRCUIT

(a) Disconnect the instrument panel wire from the airbag sensor assembly.

*1	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor Assembly
*a	Front view of wire harness connector (to Instrument Panel Passenger Airbag Assembly)
*b	Color: Green

(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
g3-2 (VHP+) - Body ground	Power switch on (IG)	Below 1 V
g3-1 (VHP-) - 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
g3-2 (VHP+) - g3-1 (VHP-)	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
g3-2 (VHP+) - Body ground	Always	1 MΩ or higher
g3-1 (VHP-) - 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
g3-2 (VHP+) - g3-1 (VHP-)	Always	1 MΩ or higher

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

GO TO STEP 5

CHECK DTC

(a) Connect the connectors to the instrument panel passenger airbag assembly and airbag sensor assembly.

*1	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor 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 B181A, B181B, B181C or B181D is not output.

HINT:

Codes other than DTCs B181A, B181B, B181C and B181D may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

REPLACE AIRBAG SENSOR ASSEMBLY

5.	CHECK INSTRUMENT PANEL WIRE

(a) Disconnect the No. 2 instrument panel wire from the instrument panel wire.

*1	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor Assembly
*3	No. 2 Instrument Panel Wire
*4	Instrument Panel Wire
*a	Front view of wire harness connector (to No. 2 Instrument Panel Wire)

(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
Ig2-1 (P3+) - Body ground	Power switch on (IG)	Below 1 V
Ig2-2 (P3-) - 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
Ig2-1 (P3+) - Ig2-2 (P3-)	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
Ig2-1 (P3+) - Body ground	Always	1 MΩ or higher
Ig2-2 (P3-) - 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
Ig2-1 (P3+) - Ig2-2 (P3-)	Always	1 MΩ or higher

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

REPLACE INSTRUMENT PANEL WIRE

6.	CHECK NO. 2 INSTRUMENT PANEL WIRE

(a) 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
g3-2 (VHP+) - Body ground	Power switch on (IG)	Below 1 V
g3-1 (VHP-) - 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	Instrument Panel Passenger Airbag Assembly
*2	Airbag Sensor Assembly
*3	No. 2 Instrument Panel Wire
*4	Instrument Panel Wire
*a	Front view of wire harness connector (to Instrument Panel Passenger Airbag Assembly)
*b	Color: Green

(b) 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
g3-2 (VHP+) - g3-1 (VHP-)	Always	Below 1 Ω

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
g3-2 (VHP+) - Body ground	Always	1 MΩ or higher
g3-1 (VHP-) - Body ground	Always	1 MΩ or higher

(d) Check for a short in the circuit.

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

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
g3-2 (VHP+) - g3-1 (VHP-)	Always	1 MΩ or higher

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

USE SIMULATION METHOD TO CHECK

REPLACE NO. 2 INSTRUMENT PANEL WIRE