Inspection Procedure

HINT:

When using the intelligent tester, start from *1. When not using the intelligent tester, start from *2.

READ VALUE OF INTELLIGENT TESTER (OIL PRESSURE SENSOR)

Check the DATA LIST for proper functioning of the master cylinder pressure sensor (oil pressure sensor).

Skid control ECU assembly

DATA LIST

Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
MAS CYL PRS 1	Master cylinder pressure 1 / Min.: 0 V, Max.: 5 V	When 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 4

NG: Go to Next step

CHECK MASTER CYLINDER PRESSURE SENSOR (OIL PRESSURE SENSOR)

Install SST (LSPV gauge) to the front caliper bleeder plug portion, and bleed LSPV gauge.
SST 09709-29018
Remove the master cylinder cover.

Start the engine and depress the brake pedal, and then check the relation between the fluid pressure and voltage of terminals 22 (PMC) and 12 (E2) of the oil pressure sensor with the connector still connected.

Fig 1: Identifying A39 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard voltage

VOLTAGE SPECIFICATION

Front Brake Caliper Fluid Pressure	Voltage
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 between terminals 10 (VCM) and 12 (E2) is 4.7 to 5.3 V.

NG: REPLACE MASTER CYLINDER PRESSURE SENSOR

OK: Go to Next step

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - MASTER CYLINDER PRESSURE SENSOR)
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: REPLACE SKID CONTROL ECU ASSEMBLY
CHECK WHETHER OR NOT THE ECU TERMINAL STP INPUT VOLTAGE IS CHANGED WHEN THE STOP LIGHT SWITCH IS TURNED ON AND OFF
NO: CHECK STOP LIGHT SWITCH CIRCUIT

YES: REPLACE SKID CONTROL ECU ASSEMBLY