Toyota Tacoma (2015-2018) Service Manual: SRS Warning Light Remains ON

Toyota Tacoma (2015-2018) Service Manual / Supplemental Restraint Systems / Airbag System / SRS Warning Light Remains ON

DESCRIPTION

The SRS warning light is located on the combination meter assembly.

When the SRS condition is normal, the SRS warning light illuminates for approximately 6 seconds after the ignition switch is turned from off to ON, and then turns off automatically.

If there is a malfunction in the SRS, the SRS warning light illuminates or blinks to inform the driver of the problem. When terminals TC and CG of the DLC3 are connected, the SRS warning light blinks to indicate DTCs.

The airbag sensor assembly is equipped with a voltage-increase circuit (DC-DC converter) in case the source voltage decreases. When the battery voltage decreases, the voltage-increase circuit (DC-DC converter) boosts the SRS voltage up to the normal level.

Malfunctions relating to battery voltage decreases cause the SRS warning light to illuminate. However, no DTCs are recorded in the airbag sensor assembly. The SRS warning light turns off automatically when the source voltage returns to normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.
After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (See page ).

PROCEDURE

1.	CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

(a) Turn the ignition switch to ON.

(b) Check the DTCs (See page OK: ).

OK:

DTC is not output.

GO TO CAN COMMUNICATION SYSTEM

2.	INSPECT BATTERY

(a) Measure the voltage of the battery.

Standard Voltage:

Tester Connection	Condition	Specified Condition
Battery	Always	11 to 14 V

CHECK AND REPLACE BATTERY OR CHARGING SYSTEM

3.	CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

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

OK:

The connectors are properly connected.

CONNECT CONNECTORS PROPERLY

4.	CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE OF AIRBAG SENSOR ASSEMBLY)

(a) Disconnect the connector from the airbag sensor assembly.

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

(d) Operate all components of the electrical system (defogger, wipers, headlights, heater blower, etc.).

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A21-21 (IG2) - A21-25 (E1)	Ignition switch ON	11 to 14 V
A21-21 (IG2) - A21-26 (E2)	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Airbag Sensor Assembly)

REPLACE HARNESS AND CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE OF COMBINATION METER ASSEMBLY)

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

(b) Disconnect the connector from the combination meter assembly.

(d) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
C9-20 (IG+) - C9-18 (ES)	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Combination Meter Assembly)

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK SRS WARNING LIGHT

(a) Turn the ignition switch off.

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

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

(e) Turn the ignition switch to ON.

(f) Check the SRS warning light condition.

OK:

The SRS warning light turns off after the primary check period and comes on again after approximately 10 seconds.

HINT:

The primary check period lasts for approximately 6 seconds after the ignition switch is turned to ON.

REPLACE AIRBAG SENSOR ASSEMBLY

REPLACE COMBINATION METER ASSEMBLY

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