CHECK AT ASTC-ECU TERMINAL <Vehicles with ASTC>


TERMINAL VOLTAGE CHECK CHART
1.Measure the voltages between earth terminal (4), (22), (56) or (64) and each respective terminal.

2.The terminal layouts are shown in the illustrations below.
note Do not measure terminal voltage for approximately three seconds after the ignition switch is turned to the "ON" position. The ASTC-ECU performs the initial check during that period.
Terminal No.
 Check item
 Checking requirements
 Normal condition
9
 ASTC-ECU power supply
 Ignition switch: ON
 System voltage
11
 Pressure switch (Pump motor control)
 Ignition switch: ON
 Brake fluid pressure: LOW
(Pump motor operates.)
 Approx. 6 V
Brake fluid pressure: HIGH
(Pump motor does not operate.)
 Less than 2 V
12
 Pump motor current detection (-)
 Ignition switch: ON
 Less than 2 V
14
 Pump motor current detection (+)
 Ignition switch: ON
 Pump motor does not operate.
 Less than 2 V
Pump motor operates.
 System voltage
24
 Motor relay B
 Ignition switch: ON
 Pump motor does not operate.
 System voltage
Pump motor operates.
 Less than 2 V
25
 Pump motor monitor
 Ignition switch: ON
 Less than 2 V
48
 Motor relay A
 Ignition switch: ON
 Pump motor does not operate.
 System voltage
Pump motor operates.
 Less than 2 V
54
 Buzzer
 Ignition switch: ON
 Buzzer does not sound.
 System voltage
Buzzer sounds.
 Less than 2 V
57
 Pressure switch (low-pressure warning)
 Ignition switch: ON
 Brake fluid pressure: EXTRA LOW
(Buzzer sounds.)
 Approx. 9 V
Brake fluid pressure: NORMAL
(Buzzer does not sound.)
 Approx. 4 V
63
 M-ASTC-ECU power supply
 Ignition switch: ON
 System voltage
81
 Brake warning light
 Engine: Idling
 The warning light does not illuminate.
 Less than 2 V
The warning light illuminates.
 System voltage

RESISTANCE AND CONTINUITY BETWEEN HARNESS-SIDE CONNECTOR TERMINALS
1.Turn the ignition switch to the "LOCK" (OFF) position.
2.Resistance measurement and continuity inspection must be performed with ASTC-ECU connector disconnected.
3.Resistance continuity inspection is performed between the terminals shown in the following table.

4.Individual terminals are arranged as shown in the figure:
Terminal No.
 Signal
 Normal condition
4 - body earth
 Earth
 Continuity (Less than 2 ohms)
22 - body earth
 Earth
56 - body earth
 Earth
64 - body earth
 Earth