Toyota 4Runner: Reservoir Level Switch Disconnected (C1453,C1454)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Reservoir Level Switch Disconnected (C1453,C1454)

DESCRIPTION

The brake fluid level warning switch sends the appropriate signal to the skid control ECU when the brake fluid level drops.

DTC Code	DTC Detection Condition	Trouble Area
C1453	With the ECU terminal IG1 voltage at 10 to 14 V, an open in the brake fluid level warning switch circuit continues for 2 seconds or more.	Brake fluid level Brake fluid level warning switch (Brake master cylinder reservoir assembly) Harness or connector Master cylinder solenoid (Skid control ECU)
C1454	The fluid level of the reservoir is LOW for 40 seconds after the ignition switch is turned to ON, or for 7 seconds during pump motor operation.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the master cylinder solenoid, perform calibration (See page ).

PROCEDURE

1.	CHECK BRAKE FLUID LEVEL

(a) Turn the ignition switch off.

(b) Depress the brake pedal 40 times or more (until the pedal reaction feels light and pedal stroke becomes longer).

HINT:

When the ignition switch is turned to ON, brake fluid is sent to the accumulator and the fluid level decreases by approximately 5 mm (0.197 in.) from the level when the ignition switch is off (normal).

OK:

Brake fluid level is normal.

CHECK AND REPAIR BRAKE FLUID LEAKAGE

2.	INSPECT BRAKE FLUID LEVEL WARNING SWITCH

(a) Disconnect the A8 brake fluid level warning switch connector.

(b) Measure the resistance according to the value(s) in the table below.

HINT:

A float is placed inside the reservoir. Its position can be changed by increasing/decreasing the level of brake fluid.

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
1 (GND) - 2 (LBL)	Float UP (Switch off)	1.9 to 2.1 kΩ
1 (GND) - 2 (LBL)	Float DOWN (Switch on)	Below 1 Ω

Text in Illustration

*a	Component without harness connected (Brake Fluid Level Warning Switch)

HINT:

If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.

REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY

3.	CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE FLUID LEVEL WARNING SWITCH)

(a) Disconnect the A6 skid control ECU connector.

(b) Disconnect the A8 brake fluid level warning switch connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A6-41 (LBL) - A8-2 (LBL)	Always	Below 1 Ω
A6-41 (LBL) - Body ground	Always	10 kΩ or higher
A8-1 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	RECONFIRM DTC

(a) Clear the DTCs (See page ).

(b) Turn the ignition switch off.

(d) Check if the same DTCs are output.

Result

Result	Proceed to
DTC is output	A
DTC is not output	B

REPLACE MASTER CYLINDER SOLENOID

USE SIMULATION METHOD TO CHECK

Accumulator Low Pressure (C1452)

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DESCRIPTION DTC Code DTC Detection Conditions Trouble Area U0073 One of the following conditions is met: When the IG1 termin ...

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