Toyota CH-R Service Manual: SRS Warning Light does not Come ON

Toyota CH-R Service Manual / Supplemental Restraint Systems / Airbag System / SRS Warning Light does not Come 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 goes 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 sensor assembly, combination meter assembly or wire harness connected to the airbag sensor assembly or combination meter assembly, the SRS warning light turns on.

When terminals TC and CG of the DLC3 are connected, DTCs are displayed by blinking of the SRS warning light.

The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the 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 stored in the 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 airbag sensor assembly to the combination meter assembly via CAN communication.

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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  • 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 BATTERY VOLTAGE

(a) Measure the voltage of the battery.

Standard Voltage:

11 to 14 V

NG

INSPECT CHARGING SYSTEM AND BATTERY

OK

2.

CHECK CONNECTOR

(a) Turn the ignition switch off.

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

CAUTION:

Wait at least 90 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 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.

(d) Disconnect the connector from the combination meter 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 CONNECTOR
OK

3.

CHECK WIRE HARNESS (COMBINATION METER ASSEMBLY - 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 ON.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

F4-39 (IG+) - Body ground

Ignition switch ON

11 to 14 V

F4-40 (B) - Body ground

Ignition switch off

11 to 14 V

(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

F4-21 (ET) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE WIRE HARNESS
OK

4.

CHECK SRS WARNING LIGHT

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

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

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

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

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

(e) Turn the ignition switch 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 ON.

OK

REPLACE AIRBAG SENSOR ASSEMBLY

NG

REPLACE COMBINATION METER ASSEMBLY

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