Inspection Procedure

NOTE: When replacing the brake actuator assembly, perform zero point calibration (See CALIBRATION ).

READ VALUE USING TECHSTREAM (DOWNHILL ASSIST CONTROL SWITCH)

Check the Data List for proper functioning of the downhill assist control switch.

ABS/VSC/TRAC:

ABS/VSC/TRAC REFERENCE CHART

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Downhill Assist Control Switch	Downhill assist control switch / ON or OFF	ON: Downhill assist control switch is on OFF: Downhill assist control switch is off	-

OK: The Techstream displays ON or OFF according to downhill assist control switch operation.

NG : Go to step 3

OK : Go to Next Step

PERFORM TEST MODE (SIGNAL CHECK)
1. Turn the ignition switch off.
2. Perform the sensor check in the Test Mode procedure (See TEST MODE PROCEDURE ).
OK: All Test Mode DTCs are cleared.

HINT:

If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (See PROBLEM SYMPTOMS TABLE ).

NG : REPLACE BRAKE ACTUATOR ASSEMBLY (See REMOVAL )

OK : CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (See HOW TO PROCEED WITH TROUBLESHOOTING )

INSPECT DOWNHILL ASSIST CONTROL SWITCH

Turn the ignition switch off.
Make sure that there is no looseness in the locking part and connecting part of the connector.
Disconnect the downhill assist control switch connector.
Measure the resistance according to the value(s) in the table below.

Standard Resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Switch Condition	Specified Condition
1 - 4	Switch is pushed	Below 1 Ω
1 - 4	Switch is not pushed	10 kΩ or higher

NOTE: Check the downhill assist control switch signal after replacement (See TEST MODE PROCEDURE ).

NG : REPLACE DOWNHILL ASSIST CONTROL SWITCH (See DOWNHILL ASSIST CONTROL SWITCH )

Fig 1: Inspecting Downhill Assist Control Switch

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : Go to Next Step

CHECK HARNESS AND CONNECTOR (DOWNHILL ASSIST CONTROL SW - SKID CONTROL ECU/BODY GROUND)

Disconnect the skid control ECU connector.
Disconnect the downhill assist control switch connector.
Measure the resistance according to the value(s) in the table below.

Standard Resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
A19-29 (HDCS) - E31-4	Always	Below 1 Ω
A19-29 (HDCS) - Body ground	Always	10 kΩ or higher
E31-1 - Body ground	Always	Below 1 Ω

HINT:

If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (See PROBLEM SYMPTOMS TABLE ).

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying Downhill Assist Control Switch And Skid Control ECU Connector Terminals

OK : REPLACE BRAKE ACTUATOR ASSEMBLY (See REMOVAL )