Toyota Tundra. Manual — part 2562

boosting transformer when the battery voltage falls below a predetermined level.

6. Diagnostic circuit

This circuit constantly diagnoses system malfunctions. When a malfunction is detected, it
turns on the SRS warning light on the combination meter to inform the driver.

7. Memory circuit

When a malfunction is detected in the diagnostic circuit, it is coded and stored in the memory
circuit.

e. SRS WARNING LIGHT

1. The SRS warning light is located on the combination meter. It comes on to inform the driver

of system trouble when a malfunction is detected in the self-diagnosis of the center airbag
sensor. Under normal operating conditions when the ignition switch is turned ON, it comes
on for approximately 6 seconds and then goes off.

3. DEPLOYMENT CONDITION

If the vehicle collides and the shock is greater than the specified value, the SRS is activated automatically.
The center airbag sensor includes the safing sensor and deceleration sensor. The safing sensor is designed
to turn on at a lower deceleration rate than the deceleration sensor.

a. The center airbag sensor determines whether ignition is necessary based on signals from the

deceleration sensor and the front airbag sensor. If the safing sensor turns on simultaneously, current
flows to the squibs to deploy the SRS as shown below.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

Fig. 37: Identifying Operation Diagram For Center Airbag Sensor (1 Of 3)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:

*: In case of a front collision, the ignition signal could be output with the deceleration sensor ON
signal even without a signal from the front airbag sensor.

b. The center airbag sensor determines whether ignition is necessary based on signals from the side

airbag sensor. If the safing sensor turns on simultaneously, current flows to the squib to deploy the
SRS as shown below.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

Fig. 38: Identifying Operation Diagram For Center Airbag Sensor (2 Of 3)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

c. The center airbag sensor determines whether ignition is necessary based on signals from the side

airbag sensor. If the safing sensor turns on simultaneously, current flows to the squib to deploy the
SRS as shown below.

Fig. 39: Identifying Operation Diagram For Center Airbag Sensor (3 Of 3)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:

*: If the front seat side airbag deploys, the curtain shield airbag will also deploy, regardless of
whether the signal is output from the side airbag sensor.

HOW TO PROCEED WITH TROUBLESHOOTING

HINT:



Use these procedures to troubleshoot the airbag system.



*: Use the Techstream.

1. VEHICLE BROUGHT TO WORKSHOP

2. INSPECT BATTERY VOLTAGE

Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

3. CHECK CAN COMMUNICATION SYSTEM*

a. Check for DTC (see DTC CHECK/CLEAR ).

Result

RESULT TABLE

B: CHECK CAN COMMUNICATION SYSTEM (see CAN COMMUNICATION SYSTEM )

A: Go to next step

4. WARNING LIGHT CHECK

a. Check the warning light (see DIAGNOSIS SYSTEM ).

5. CHECK DTC (Present and Past DTCs)*

a. Check for DTC (see DTC CHECK/CLEAR ).

Result

RESULT TABLE

B: See PROBLEM SYMPTOMS TABLE

A: Go to next step

6. DTC TABLE

7. CIRCUIT INSPECTION

8. REPAIR

9. CLEAR DTC (Present and Past DTCs)*

10. CHECK DTC (Present and Past DTCs)*

a. Check for DTC (see DTC CHECK/CLEAR ).

Result

RESULT TABLE

Result

Proceed to

DTC is not output

A

DTC is output

B

Result

Proceed to

DTC is output

A

DTC is not output

B

Result

Proceed to

DTC is not output

A

DTC is output

B

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra