Supplemental Restraint Systems. Airbag System Srs Warning Light Remains On

The SRS warning light is located on 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 goes off automatically.
If there is a malfunction in the SRS, the SRS warning light comes on to inform the driver of a problem.
When terminals TC and CG of the DLC3 are connected, the DTC is indicated by blinking pattern of the SRS warning light.
The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the center airbag sensor assembly in case the 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.
A malfunction in this circuit is not recorded in the center airbag sensor assembly. The SRS warning light automatically goes off when the source voltage returns to normal.
The signal to illuminate the SRS warning light is transmitted from the center airbag sensor assembly to the combination meter assembly through the CAN communication system.

WIRING DIAGRAM

Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System.Airbag System Srs Warning Light Remains On

INSPECTION PROCEDURE

1.CHECK SRS WARNING LIGHT OPERATION

Check the SRS warning light operation approximately 6 seconds after the ignition switch is turned to ON.

Result:

SRS Warning Light Illumination
Proceed to
Remains on
A
Remains on after it goes off
B

Go to step 6

A

2.CHECK BATTERY VOLTAGE

Measure the voltage of the battery.
Standard Voltage:
11 to 14 V
Result
Result
Proceed to
OK
A
NG (for 2AZ-FE)
B
NG (for 2ZR-FE)
C

Result
Result	Proceed to
OK	A
NG (for 2AZ-FE)	B
NG (for 2ZR-FE)	C

INSPECT CHARGING SYSTEM AND BATTERY (COROLLA_ZRE142 RM000001AR909TX.html)

INSPECT CHARGING SYSTEM AND BATTERY (COROLLA_ZRE142 RM000001AR909SX.html)

A

3.CHECK CONNECTOR

Turn the ignition switch off.

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

Check that the connector is properly connected to the center airbag sensor assembly.
OK:
The connector is properly connected.
HINT:
If the connector is not connected securely, reconnect the connector and proceed to the next inspection.

Disconnect the connector from the center airbag sensor assembly.

Check that the terminal of the connector is not damaged.
OK:
The terminal is not deformed or damaged.

REPLACE WIRE HARNESS

OK

4.CHECK WIRE HARNESS (CENTER AIRBAG SENSOR ASSEMBLY - BODY GROUND)

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

Turn the ignition switch to ON.

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

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
E14-21 (IG2) - Body ground
Ignition switch ON
8 to 16 V

Turn the ignition switch off.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
E14-25 (E1) - Body ground
Always
Below 1 Ω
E14-26 (E2) - Body ground
Always
Below 1 Ω

REPLACE WIRE HARNESS

OK

5.CHECK SRS WARNING LIGHT

Turn the ignition switch to ON.

Check the SRS warning light condition.
OK:
After the primary check period, the SRS warning light goes off for approximately 10 seconds and remains on.
HINT:
The primary check period is approximately 6 seconds after the ignition switch is turned to ON.

REPLACE COMBINATION METER ASSEMBLY (COROLLA_ZRE142 RM0000024D7032X.html)

REPLACE CENTER AIRBAG SENSOR ASSEMBLY (COROLLA_ZRE142 RM000000UWV074X.html)

6.CHECK CAN COMMUNICATION SYSTEM

Use the Techstream to check if the CAN communication system is functioning normally.
HINT:
1. Refer to Bus Check for the CAN communication system (COROLLA_ZRE142 RM000000WIB0BUX.html)
  A
  
  7.CHECK BATTERY VOLTAGE
  1. Measure the voltage of the battery.
    Standard Voltage:
    11 to 14 V
    Result
    Result
    Proceed to
    OK
    A
    NG (for 2AZ-FE)
    B
    NG (for 2ZR-FE)
    C
  B
  INSPECT CHARGING SYSTEM AND BATTERY (COROLLA_ZRE142 RM000001AR909TX.html)
  
  C
  INSPECT CHARGING SYSTEM AND BATTERY (COROLLA_ZRE142 RM000001AR909SX.html)
  A
  
  8.CHECK CONNECTOR
  1. Turn the ignition switch off.
  1. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
  1. Check that the connector is properly connected to the center airbag sensor assembly.
    OK:
    The connector is properly connected.
    HINT:
    If the connector is not connected securely, reconnect the connector and proceed to the next inspection.
  1. Disconnect the connector from the center airbag sensor assembly.
  1. Check that the terminal of the connector is not damaged.
    OK:
    The terminal is not deformed or damaged.
  NG
  REPLACE WIRE HARNESS
  OK
  
  9.CHECK WIRE HARNESS (CENTER AIRBAG SENSOR ASSEMBLY - BODY GROUND)
  1. Connect the cable to the negative (-) battery terminal.
  1. Turn the ignition switch to ON.
  1. Operate all components of the electrical system (defogger, wipers, headlights, heater blower, etc.).
  1. Measure the voltage according to the value(s) in the table below.
    Standard Voltage:
    Tester Connection
    Switch Condition
    Specified Condition
    E14-21 (IG2) - Body ground
    Ignition switch ON
    8 to 16 V
  1. Turn the ignition switch off.
  1. Measure the resistance according to the value(s) in the table below.
    Standard Resistance:
    Tester Connection
    Condition
    Specified Condition
    E14-25 (E1) - Body ground
    Always
    Below 1 Ω
    E14-26 (E2) - Body ground
    Always
    Below 1 Ω
  NG
  REPLACE WIRE HARNESS
  OK
  
  10.CHECK CONNECTOR
  1. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
  1. Check that the connector is properly connected to the combination meter assembly.
    OK:
    The connector is properly connected.
    HINT:
    If the connector is not connected securely, reconnect the connector and proceed to the next inspection.
  1. Disconnect the connector from the combination meter assembly.
  1. Check that the terminal of the connector is not damaged.
    OK:
    The terminal is not deformed or damaged.
  NG
  REPLACE WIRE HARNESS
  OK
  
  11.CHECK WIRE HARNESS (COMBINATION METER ASSEMBLY - BODY GROUND)
  1. Connect the cable to the negative (-) battery terminal.
  1. Turn the ignition switch to ON.
  1. Measure the voltage according to the value(s) in the table below.
    Standard Voltage:
    Tester Connection
    Condition
    Specified Condition
    E46-32 (B) - Body ground
    Always
    11 to 14 V
    E46-33 (IG+) - Body ground
    Ignition switch ON
    11 to 14 V
  1. Turn the ignition switch off.
  1. Measure the resistance according to the value(s) in the table below.
    Standard Resistance:
    Tester Connection
    Condition
    Specified Condition
    E46-30 (ET) - Body ground
    Always
    Below 1 Ω
  NG
  REPLACE WIRE HARNESS
  OK
  
  12.CHECK SRS WARNING LIGHT
  1. Connect the connector to the combination meter assembly.
  1. Connect the cable to the negative (-) battery terminal.
  1. Turn the ignition switch to ON.
  1. Check the SRS warning light condition.
    OK:
    After the primary check period, the SRS warning light goes off for approximately 10 seconds and remains on.
    HINT:
    The primary check period is approximately 6 seconds after the ignition switch is turned to ON.
  NG
  REPLACE COMBINATION METER ASSEMBLY (COROLLA_ZRE142 RM0000024D7032X.html)
  OK
  
  REPLACE CENTER AIRBAG SENSOR ASSEMBLY (COROLLA_ZRE142 RM000000UWV074X.html)

SRS Warning Light Illumination	Proceed to
Remains on	A
Remains on after it goes off	B

Tester Connection	Switch Condition	Specified Condition
E14-21 (IG2) - Body ground	Ignition switch ON	8 to 16 V

Tester Connection	Condition	Specified Condition
E14-25 (E1) - Body ground	Always	Below 1 Ω
E14-26 (E2) - Body ground	Always	Below 1 Ω