Toyota 4Runner: Certification ECU Communication Stop Mode

Toyota 4Runner Service Manual / Power Source / Network / Networking / Can Communication System / Certification ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptoms	Trouble Area
Certification ECU Communication Stop Mode	Either condition is met: "Certification (Smart)" is not displayed on the "CAN Bus Check" screen. "Certification ECU Communication Stop Mode" in "DTC Combination Table" applies.	Power source or inside certification ECU Certification ECU branch wire or connector Certification ECU

HINT:

For vehicles with a smart key system only.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

1.	DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire or branch wire.

CAUTION:

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

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

2.	CHECK FOR OPEN IN CAN BUS WIRE (CERTIFICATION ECU BRANCH WIRE)

(a) Disconnect the F79 certification ECU connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F79-9 (CANH) - F79-10 (CANL)	Ignition switch off	54 to 69 Ω

Text in Illustration

*a	Rear view of wire harness connector (to Certification ECU)

REPAIR OR REPLACE CERTIFICATION ECU BRANCH WIRE OR CONNECTOR (CANH, CANL)

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

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

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F79-15 (E) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F79-1 (+B) - Body ground	Always	11 to 14 V
F79-16 (IG) - Body ground	Ignition switch ON	11 to 14 V
F79-17 (CUTB) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Certification ECU)

REPLACE CERTIFICATION ECU

REPAIR OR REPLACE HARNESS OR CONNECTOR

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