Toyota Corolla Cross: SRS Warning Light Remains ON

DESCRIPTION

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

When the SRS is normal, the SRS warning light comes on 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 comes on to inform the driver of a problem.

If a malfunction occurs in the airbag ECU assembly, combination meter assembly or wire harness connected to the airbag ECU assembly or combination meter assembly, the SRS warning light comes on.

The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the airbag ECU assembly in case the power source voltage drops.

When the battery voltage drops, the voltage-increase circuit (DC-DC converter) functions to increase the voltage of the SRS to normal voltage. In addition, when the voltage drops, the SRS warning light will illuminate.

The SRS warning light automatically turns off when the power source voltage returns to normal.

The signal to illuminate the SRS warning light is transmitted from the airbag ECU assembly to the combination meter assembly via CAN communication.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

• After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) battery terminal.

  Click here

  HINT:

  When disconnecting and reconnecting the battery, there is an automatic learning function that completes learning when the respective system is used.

  Click here

• Inspect the fuses for circuits related to this system before performing the following procedure.
• When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

PROCEDURE

1.	CHECK VEHICLE CONTROL HISTORY (RoB)

(a) Check for Vehicle Control History (RoB) codes.

Body Electrical > SRS Airbag > Utility

Tester Display
Vehicle Control History (RoB)

Result	Proceed to
Code X210B is output	A
Code X210B is not output	B

B

GO TO STEP 4

A

2.	CHECK BATTERY VOLTAGE

(a) Measure the voltage of the battery with the ignition switch off.

Standard Voltage:

11 to 14 V

NG

REPLACE OR RECHARGE BATTERY

OK

3.	CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - BATTERY AND BODY GROUND)

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

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

(b) Turn the ignition switch to ON.

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I47-36 (IGR) - Body ground	Ignition switch ON	8 to 16 V

(e) Turn the ignition switch off.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I47-33 (E1) - Body ground	Always	Below 1 Ω
I47-32 (E2) - Body ground	Always	Below 1 Ω

OK

END (POWER SOURCE VOLTAGE DROPPED TEMPORARILY, BUT HAS RETURNED TO NORMAL)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK SRS WARNING LIGHT OPERATION

(a) Turn the ignition switch to ON and check the SRS warning light condition.

HINT:

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

Result	Proceed to
After the primary check period, the SRS warning light remains on.	A
After the primary check period, the SRS warning light turns off and comes on again.	B

B

GO TO STEP 9

A

5.	CHECK BATTERY VOLTAGE

(a) Measure the voltage of the battery with the ignition switch off.

Standard Voltage:

11 to 14 V

NG

REPLACE OR RECHARGE BATTERY

OK

6.	CHECK CONNECTOR (AIRBAG ECU ASSEMBLY SIDE)

(a) Turn the ignition switch off.

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

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connector is properly connected to the airbag ECU assembly.

OK:

The connector is properly connected.

HINT:

If the connector is not properly connected, reconnect the connector and proceed to the next inspection.

(d) Disconnect the connector from the airbag ECU assembly.

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

OK:

The terminals are not deformed or damaged.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.	CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - BATTERY AND BODY GROUND)

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

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

(b) Turn the ignition switch to ON.

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I47-36 (IGR) - Body ground	Ignition switch ON	8 to 16 V

(e) Turn the ignition switch off.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I47-33 (E1) - Body ground	Always	Below 1 Ω
I47-32 (E2) - Body ground	Always	Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.	CHECK SRS WARNING LIGHT

(a) Turn the ignition switch to ON and check the SRS warning light condition. OK: After the primary check period, the SRS warning light turns off for approximately 10 seconds and then turns back on. HINT: The primary check period is approximately 6 seconds after the ignition switch is turned to ON.

*1 Combination Meter Assembly *2 Airbag ECU Assembly *3 Wire Harness

OK

REPLACE AIRBAG ECU ASSEMBLY

NG

REPLACE COMBINATION METER ASSEMBLY

9.	CHECK CAN COMMUNICATION SYSTEM

(a) Using the GTS, check if the CAN communication system is functioning normally.

OK:

CAN communication system is functioning normally.

HINT:

Refer to Communication Bus Check in CAN Communication System.

• for HEV Model:

  Click here

• for Gasoline Model:

  Click here

NG

GO TO CAN COMMUNICATION SYSTEM for HEV Model: Click here for Gasoline Model: Click here

OK

10.	CHECK BATTERY VOLTAGE

(a) Measure the voltage of the battery with the ignition switch off.

Standard Voltage:

11 to 14 V

NG

REPLACE OR RECHARGE AUXILIARY BATTERY

OK

11.	CHECK CONNECTOR (AIRBAG ECU ASSEMBLY SIDE)

(a) Turn the ignition switch off.

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

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connector is properly connected to the airbag ECU assembly.

OK:

The connector is properly connected.

HINT:

If the connector is not properly connected, reconnect the connector and proceed to the next inspection.

(d) Disconnect the connector from the airbag ECU assembly.

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

OK:

The terminals are not deformed or damaged.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

12.	CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - BATTERY AND BODY GROUND)

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

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

(b) Turn the ignition switch to ON.

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I47-36 (IGR) - Body ground	Ignition switch ON	8 to 16 V

(e) Turn the ignition switch off.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I47-33 (E1) - Body ground	Always	Below 1 Ω
I47-32 (E2) - Body ground	Always	Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

13.	CHECK CONNECTOR (COMBINATION METER ASSEMBLY SIDE)

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

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(b) Check that the connector is properly connected to the combination meter assembly.

OK:

The connector is properly connected.

HINT:

If the connector is not properly connected, reconnect the connector and proceed to the next inspection.

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

(d) Check that the terminals of the connector are not deformed or damaged.

OK:

The terminals are not deformed or damaged.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

14.	CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BATTERY AND BODY GROUND)

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

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

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I4-6 (IG+) - Body ground	Ignition switch ON	10.5 to 16 V*1
		11 to 14 V*2

• *1: w/ Stop and Start System
• *2: w/o Stop and Start System

(d) Turn the ignition switch off.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I4-1 (EP) - Body ground	Always	Below 1 Ω
I4-2 (ES) - Body ground	Always	Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

15.	CHECK SRS WARNING LIGHT

(a) Disconnect the cable from the negative (-) battery terminal. CAUTION: Wait at least 60 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

*1 Combination Meter Assembly *2 Airbag ECU Assembly *3 Wire Harness

(b) Connect the connector to the combination meter assembly.

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

(d) Turn the ignition switch to ON and check the SRS warning light condition.

OK:

After the primary check period, the SRS warning light turns off for approximately 10 seconds and then turns back on.

HINT:

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

OK

REPLACE AIRBAG ECU ASSEMBLY

NG

REPLACE COMBINATION METER ASSEMBLY

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