Toyota 4Runner: Diagnosis Circuit

Toyota 4Runner Service Manual / Vehicle Interior / Supplemental Restraint Systems / Airbag System / Diagnosis Circuit

DESCRIPTION

DTC output mode is set by connecting terminals TC and CG of the DLC3.

DTCs are output by the blinking of the SRS warning light.

HINT:

When each warning light continues blinking, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in each ECU is suspected.
A DTC output mode signal is transmitted through the CAN communication system to each ECU including the center airbag sensor. Thus, when all systems do not enter DTC output mode, there may be an ECM malfunction.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected (See page ).

PROCEDURE

1.	CHECK CAN COMMUNICATION SYSTEM

(a) Check if a CAN communication system DTC is output (See page ).

Result

Result	Proceed to
DTC is not output	A
DTC is output	B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

2.	CHECK HARNESS AND CONNECTOR (DLC3 - ECM)

(a) Turn the ignition switch off.

(b) Disconnect the F50 connector from the ECM.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F13-13 (TC) - F50-28 (TC)	Always	Below 1 Ω

Text in Illustration

Front view of DLC3

Rear view of wire harness connector

(to ECM)

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK HARNESS AND CONNECTOR (DLC3 - BODY GROUND)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
E22-4 (CG) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of DLC3

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F50-28 (TC) - Body ground	Always	1 MΩ or higher

Text in Illustration

*a	Rear view of wire harness connector (to ECM)

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU

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