Toyota Tacoma 2015-2018 Service Manual: Problem Symptoms Table

Toyota Tacoma 2015-2018 Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Vacuum Brake Booster) / Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

NOTICE:

When replacing the skid control ECU (brake actuator assembly), sensor, etc., turn the ignition switch off.

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
Inspect the fuses and relays related to this system before inspecting the suspected areas below.

Vehicle Stability Control System

Symptom	Suspected Area	See page
ABS, BA and/or EBD does not operate efficiently	Check for DTCs again and make sure that the normal system code is output.
	Power source circuit (low power supply voltage malfunction)
	Power source circuit (high power supply voltage malfunction)
	Front speed sensor circuit (comparison malfunction)
	Front speed sensor circuit (open or short malfunction)
	Front speed sensor circuit (output malfunction)
	Rear speed sensor circuit (comparison malfunction)
	Rear speed sensor circuit (open or short malfunction)
	Rear speed sensor circuit (output malfunction)
	Check the skid control ECU (brake actuator assembly) with the Techstream. (Check skid control ECU (brake actuator assembly) operation using the Active Test function.) If abnormal, check the hydraulic circuit for leaks.
	If the symptoms still occur even after the above circuits in suspected areas have been inspected and proved to be normal, replace the skid control ECU (brake actuator assembly).
	Check for DTCs again and make sure that the normal system code is output.
	Front speed sensor circuit (comparison malfunction)
	Front speed sensor circuit (open or short malfunction)
	Front speed sensor circuit (output malfunction)
	Rear speed sensor circuit (comparison malfunction)
	Rear speed sensor circuit (open or short malfunction)
	Rear speed sensor circuit (output malfunction)
	Stop light switch circuit
	Check the skid control ECU (brake actuator assembly) with the Techstream. (Check skid control ECU (brake actuator assembly) operation using the Active Test function.) If abnormal, check the hydraulic circuit for leaks.
	If the symptoms still occur even after the above circuits in suspected areas have been inspected and proved to be normal, replace the skid control ECU (brake actuator assembly).
ABS sensor DTC check cannot be done	Check for DTCs again and make sure that the normal system code is output.
	TC and CG terminal circuit*2
	If the symptoms still occur even after the above circuit in the suspected area has been inspected and proved to be normal, replace the skid control ECU (brake actuator assembly).
ABS warning light abnormal (Remains on)	ABS warning light circuit
ABS warning light abnormal (Remains on)	Skid control ECU (brake actuator assembly)
ABS warning light abnormal (Does not come on)	ABS warning light circuit
ABS warning light abnormal (Does not come on)	Skid control ECU (brake actuator assembly)
Brake warning light abnormal (Remains on)	Brake warning light circuit
Brake warning light abnormal (Remains on)	Skid control ECU (brake actuator assembly)
Brake warning light abnormal (Does not come on)	Brake warning light circuit
Brake warning light abnormal (Does not come on)	Skid control ECU (brake actuator assembly)
VSC and/or TRAC does not operate	Check for DTCs again and make sure that the normal system code is output.
	Power source circuit (low power supply voltage malfunction)
	Power source circuit (high power supply voltage malfunction)
	Check the hydraulic circuit for leaks.	-
	Front speed sensor circuit (comparison malfunction)
	Front speed sensor circuit (open or short malfunction)
	Front speed sensor circuit (output malfunction)
	Rear speed sensor circuit (comparison malfunction)
	Rear speed sensor circuit (open or short malfunction)
	Rear speed sensor circuit (output malfunction)
	Yaw rate and acceleration sensor (airbag sensor assembly) circuit (zero point malfunction)
	Yaw rate and acceleration sensor (airbag sensor assembly) circuit (power supply malfunction)
	Acceleration sensor (airbag sensor assembly) circuit (comparison malfunction)
	Yaw rate sensor (airbag sensor assembly) circuit (comparison malfunction)
	Yaw rate and acceleration sensor (airbag sensor assembly) circuit (stuck or output malfunction)
	Yaw rate and acceleration sensor (airbag sensor assembly) circuit (internal malfunction)
	Steering angle sensor (Spiral cable with sensor sub-assembly) circuit (zero point malfunction)
	Steering sensor (Spiral cable with sensor sub-assembly) circuit (Zero point initialization or calibration malfunction)
	Steering angle sensor (Spiral cable with sensor sub-assembly) circuit (power supply malfunction)
	Steering angle sensor (Spiral cable with sensor sub-assembly) circuit (output malfunction)
	Steering angle sensor (Spiral cable with sensor sub-assembly) circuit (internal malfunction)
	If the symptoms still occur even after the above circuit in suspected areas have been inspected and proved to be normal, replace the skid control ECU (brake actuator assembly).
VSC sensor DTC check cannot be done	Check for DTCs again and make sure that the normal system code is output.
	TC and CG terminal circuit*2
	If the symptoms still occur even after the above circuit in suspected areas has been inspected and proved to be normal, replace the skid control ECU (brake actuator assembly).
VSC OFF switch abnormal	VSC OFF switch circuit
VSC OFF switch abnormal	Skid control ECU (brake actuator assembly)
AUTO LSD indicator light abnormal (Remains on)	AUTO LSD indicator circuit
AUTO LSD indicator light abnormal (Remains on)	Skid control ECU (brake actuator assembly)
AUTO LSD indicator light abnormal (Does not come on)	AUTO LSD indicator circuit
AUTO LSD indicator light abnormal (Does not come on)	Skid control ECU (brake actuator assembly)
Slip indicator light abnormal (Remains on)	Slip indicator light circuit
	Skid control ECU (brake actuator assembly)
	The rear differential lock indicator light blinks when the rear differential cannot be unlocked for 2 consecutive trips.*1
Slip indicator light abnormal (Does not come on)	Slip indicator light circuit
Slip indicator light abnormal (Does not come on)	Skid control ECU (brake actuator assembly)
Sensor check cannot be done	TS and CG terminal circuit*2
Sensor check cannot be done	Skid control ECU (brake actuator assembly)
VSC warning buzzer abnormal	VSC warning buzzer circuit
VSC warning buzzer abnormal	Skid control ECU (brake actuator assembly)

*1: w/ Rear Differential Lock
*2: w/o Toyota Safety Sense P

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