Inspection Procedure

1. Check the DATA LIST for proper functioning of the brake actuator (master cylinder pressure sensor).

   Skid control ECU 

   DIAGNOSTIC NOTE CHART
   
   

   Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
   MAS CYL PRS 1	Master cylinder pressure sensor 1 reading / Min.: 0 V, Max.: 5 V	Brake pedal is released: 0.3 to 0.9 V	Reading increases when brake pedal is depressed
   MAS CYL PRS 2	Master cylinder pressure sensor 2 reading / Min.: 0 V, Max.: 5 V	Brake pedal is released: 0.3 to 0.9 V	Reading increases when brake pedal is depressed

   OK: Brake fluid pressure value must be changing. 

OK: Go to step  3

NG: Go to Next Step 

Fig 1: Checking Wire Harness (Skid Control ECU - Brake Actuator)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the S8 ECU connector.
2. Disconnect the M2 master cylinder connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   S8-10 (VCM) - M2-1 (VCM)	Below 1 Ω
   S8-22 (PMC) - M2-2 (PMC)	Below 1 Ω
   S8-23 (E2) - M2-3 (E2)	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to Next Step 

1. Install SST (LSPV gauge) to the front caliper bleeder plug portion, and bleed LSPV gauge.

   SST 09709-29018 

2. Remove the brake actuator cover.
3. Start the engine and depress the brake pedal. Then check the voltage of terminals 2 (PMC) and 3 (E2) of the master cylinder pressure sensor when the fluid pressure is in the following conditions with the connector still connected.

   Standard voltage 

   SPECIFIED CONDITION CHART
   
   

   Front Brake Caliper Fluid Pressure	Specified Condition
   0 kPa (0 kgf/cm2 , 0 psi)	0.37 to 0.63 V
   5,883 kPa (60 kgf/cm2 , 853 psi)	1.57 to 1.83 V
   11,768 kPa (120 kgf/cm2 , 1,706 psi)	2.77 to 3.03 V

   HINT:

   Voltage of between terminals VCM and E2: 4.7 to 5.3 V

   Fig 2: Checking Brake Actuator (Master Cylinder Pressure Sensor)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE MASTER CYLINDER PRESSURE SENSOR 

OK: REPLACE SKID CONTROL ECU