Toyota 4Runner: Brake Actuator (Skid Control ECU) Communication Stop Mode

Toyota 4Runner Service Manual / Power Source / Network / Networking / Can Communication System / Brake Actuator (Skid Control ECU) Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Brake Actuator (Skid Control ECU) Communication Stop Mode	Either condition is met: "Skid Control (ABS/VSC/TRAC)" is not displayed on the "CAN Bus Check" screen. "Brake Actuator (Skid Control ECU) Communication Stop Mode" in "DTC Combination Table" applies.	Power source or inside skid control ECU (brake actuator assembly) Skid control ECU (brake actuator assembly) branch wire or connector Skid control ECU (brake actuator assembly)

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 and 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 (SKID CONTROL ECU BRANCH WIRE)

(a) Disconnect the A53 skid control ECU (brake actuator assembly) connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
A53-25 (CANH) - A53-14 (CANL)	Ignition switch off	54 to 69 Ω

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU [Brake Actuator Assembly])

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

3.	CHECK HARNESS AND CONNECTOR (SKID CONTROL 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
A53-1 (GND1) - Body ground	Always	Below 1 Ω
A53-13 (GND2) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
A53-12 (+BS) - Body ground	Always	11 to 14 V
A53-24 (BM) - Body ground	Always	11 to 14 V
A53-34 (IG1) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU [Brake Actuator Assembly])

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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