Toyota Tacoma 2015-2018 Service Manual: Control Module Communication Bus OFF (U0073,U0100,U0124,U0126)

Toyota Tacoma 2015-2018 Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Vacuum Brake Booster) / Control Module Communication Bus OFF (U0073,U0100,U0124,U0126)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives the signals from the ECM, steering angle sensor (spiral cable with sensor sub-assembly), 4 wheel drive control ECU*, and yaw rate and acceleration sensor (airbag sensor assembly) via the CAN communication system.

*: for 4WD or w/ Rear Differential Lock

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
U0073	Control Module Communication Bus OFF	Any of the following is detected: A bus OFF state occurs once or more within 0.1 seconds, 10 times in succession. (Sent signals cannot be received.) When the +BS terminal voltage is between 10 and 17.4 V, a delay in receiving data from the yaw rate sensor and steering angle sensor continues for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession within 60 seconds. The condition that a delay in receiving data from the yaw rate sensor and steering angle sensor occurs more than once within 5 seconds.	CAN communication system
U0100	Lost Communication with ECM	When the +BS terminal voltage is between 10 and 17.4 V, and the vehicle speed is 15 km/h (9 mph) or more, data cannot be received from the ECM for 2 seconds or more.	CAN communication system Skid control ECU (Brake actuator assembly) ECM
U0124	Lost Communication with Lateral Acceleration Sensor Module	Any of the following is detected: When the +BS terminal voltage is between 10 and 17.4 V, and the vehicle speed is 7 km/h or more, data from the acceleration sensor cannot be received for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession within 60 seconds. The condition that data from the acceleration sensor cannot be received occurs once or more within 5 seconds.	CAN communication system Skid control ECU (Brake actuator assembly) Acceleration sensor (Airbag sensor assembly)
U0126	Lost Communication with Steering Angle Sensor Module	Any of the following is detected: When the +BS terminal voltage is between 10 and 17.4 V, data from the steering angle sensor cannot be received for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession. The condition that data from the steering angle sensor cannot be received occurs once or more within 5 seconds.	CAN communication system Skid control ECU (Brake actuator assembly) Steering angle sensor (Spiral cable sensor with sub-assembly)

HINT:

DTC will be output when conditions for any of the patterns in the table above are met.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

(a) Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to a DTC (See page ABS/VSC/TRAC ).

ABS/VSC/TRAC

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
EFI Communication Open	ECM communication open detection	Normal or Error	Normal	Error: Momentary interruption
Yaw Rate Open	Yaw rate sensor open detection	Normal or Error	Normal	Error: Momentary interruption
Deceleration Open	Acceleration sensor open detection	Error or Normal	Normal	Error: Momentary interruption
Steering Open	Steering angle sensor open detection	Normal or Error	Normal	Error: Momentary interruption

HINT:

Perform the above inspection before removing the sensor and connector.

Result

Result	Proceed to
There is a constant open circuit	A
There are no momentary interruptions	B
There are momentary interruptions	C

GO TO STEP 3

GO TO STEP 4

2.	CHECK IF EACH SENSOR AND ECM CONNECTOR IS SECURELY CONNECTED

(a) Turn the ignition switch off.

(b) Check if each sensor, 4 wheel drive control ECU* or ECM connector is securely connected.

*: for 4WD or w/ Rear Differential Lock

OK:

Each connector is securely connected.

CONNECT CONNECTOR TO EACH SENSOR OR ECM CORRECTLY

3.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Record the output DTCs (for VSC system and/or CAN communication system).

for VSC system: (See page )
for CAN communication system: (See page )

HINT:

If the CAN communication system DTC and the relevant sensor DTCs are output simultaneously, troubleshoot the relevant sensor DTCs (for VSC system) after the CAN communication system returns to normal.

Result

Result	Proceed to
DTC (relating to CAN communication system) is output	A
DTC (relating to VSC system) is output	B
DTC is not output	C

CHECK CAN COMMUNICATION SYSTEM

REPAIR CIRCUIT INDICATED BY OUTPUT DTC

USE SIMULATION METHOD TO CHECK

4.	REPAIR OR REPLACE HARNESS OR CONNECTOR

(a) Turn the ignition switch off.

(b) Repair or replace the harness or connector.

(c) Check for any momentary interruption between the skid control ECU (brake actuator assembly) and each sensor or ECM (See page (d) Check that there is no momentary interruption. ).

(d) Check that there is no momentary interruption.

5.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs (See page (c) Start the engine. ).

(d) Drive the vehicle at a speed of 15 km/h (9 mph) or more and turn the steering wheel to the right and left.

(e) Check that no CAN communication system DTC is output (See page (f) If VSC system DTCs are output, record them (See page ).

(f) If VSC system DTCs are output, record them (See page HINT: HINT: ).

HINT:

The CAN communication system must be normal when repairing each sensor DTC (for VSC system).

Result

Result	Proceed to
DTC is not output	A
DTC is output (relating to VSC system)	B
DTC is output (relating to CAN communication system)	C

END

REPAIR CIRCUIT INDICATED BY OUTPUT DTC

CHECK CAN COMMUNICATION SYSTEM

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