Toyota Tundra Service Manual: Short in Knee Airbag (D Side) Squib Circuit (B1860-B1863)

DESCRIPTION

The driver side knee squib circuit consists of the airbag sensor assembly and lower No. 1 instrument panel airbag assembly.

This circuit instructs the SRS to deploy when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the driver side knee squib circuit.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

• After turning the ignition 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.

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• When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected.

  Click here

HINT:

To perform the simulation method, enter check mode (signal check) with the Techstream (Click here ), and then wiggle each connector of the airbag system or drive the vehicle on various types of road (Click here ).

PROCEDURE

(a) Turn the ignition switch off.

*1 Lower No. 1 Instrument Panel Airbag Assembly *2 Airbag Sensor Assembly *3 Instrument Panel Wire

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Check that the connectors are properly connected to the lower No. 1 instrument panel airbag assembly and airbag sensor 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 lower No. 1 instrument panel airbag assembly and airbag sensor 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 instrument panel wire connector (on the lower No. 1 instrument panel airbag assembly side) is not loose, deformed or damaged.

OK:

The 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 mechanism of the instrument panel wire connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

NG

REPLACE INSTRUMENT PANEL WIRE

OK

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

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

(b) Connect the white wire side of SST (resistance: 2.1 Ω) to connector C.

CAUTION:

Never connect the tester to the lower No. 1 instrument panel 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 SST.
• Insert SST straight into the terminals of the connector.

SST: 09843-18061

(c) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(d) Turn the ignition switch to ON, and wait for at least 60 seconds.

(e) Clear the DTCs.

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(f) Turn the ignition switch off.

(g) Turn the ignition switch to ON, and wait for at least 60 seconds.

(h) Check for DTCs.

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HINT:

Codes other than DTC B1860, B1861, B1862 and B1863 may be output at this time, but they are not related to this check.

(i) Turn the ignition switch off.

(j) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(k) Disconnect SST from connector C.

A

REPLACE LOWER NO. 1 INSTRUMENT PANEL AIRBAG ASSEMBLY

B

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

*1	Lower No. 1 Instrument Panel Airbag Assembly
*2	Airbag Sensor Assembly
*3	Instrument Panel Wire
*a	Front view of wire harness connector (to Lower No. 1 Instrument Panel Airbag Assembly)
	Release the activation prevention mechanism

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

(1) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(2) Turn the ignition switch to ON.

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

Standard Voltage:

(4) Turn the ignition switch off.

(5) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Check for an open in the circuit.

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

Standard Resistance:

(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:

(e) Check for a short in the circuit.

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

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

Standard Resistance:

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

NG

REPLACE INSTRUMENT PANEL WIRE

OK

(a) Connect the connectors to the lower No. 1 instrument panel airbag assembly and airbag sensor assembly.

*1 Lower No. 1 Instrument Panel Airbag Assembly *2 Airbag Sensor Assembly

(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(c) Turn the ignition switch to ON, and wait for at least 60 seconds.

(d) Clear the DTCs.

Click here

(e) Turn the ignition switch off.

(f) Turn the ignition switch to ON, and wait for at least 60 seconds.

(g) Check for DTCs.

Click here

HINT:

Codes other than DTC B1860, B1861, B1862 and B1863 may be output at this time, but they are not related to this check.

A

USE SIMULATION METHOD TO CHECK

B

REPLACE AIRBAG SENSOR ASSEMBLY