Toyota 4Runner: Pressure Sensor or Switch (C1254)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Pressure Sensor or Switch (C1254)

DESCRIPTION

The accumulator pressure sensor is connected to the skid control ECU in the master cylinder solenoid.

DTC Code	DTC Detection Condition	Trouble Area
C1254	There is an accumulator pressure sensor malfunction (the fluid pressure does not change when the pump operates or when the brake is applied).	Master cylinder solenoid (Accumulator pressure sensor)

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the ignition switch to ON.

(e) Turn the Techstream on.

(f) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Accumulator Sensor	Accumulator pressure sensor reading/ Min.: 0.00 V, Max.: 5.00 V	3.58 to 5 V	If the value is constant regardless of the pump operation, an accumulator pressure sensor malfunction is suspected.

(g) Check the accumulator output value.

Result

Result	Proceed to
Output value is within "Normal Condition" range	A
Output value is out of "Normal Condition" range	B
Output value is constant regardless of pump operation	B

REPLACE MASTER CYLINDER SOLENOID

2.	RECONFIRM DTC

(a) Clear the DTCs (See page ).

(b) Turn the ignition switch off.

(d) Turn the ignition switch to ON.

(e) Wait until the pump motor stops.

(f) Wait for 15 minutes.

(g) Depress the brake pedal and release it.

(h) Check if the same DTC is output (See page
).

Result

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

REPLACE MASTER CYLINDER SOLENOID

USE SIMULATION METHOD TO CHECK

Pump Motor Relay (C1253)

DESCRIPTION The motor relay (semiconductor relay) is built into the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU. DTC Code D ...

Accumulator Low Pressure (C1256)

DESCRIPTION Refer to DTC C1254 (See page ). DTC Code DTC Detection Condition Trouble Area C1256 The fluid pressure inside the accumulato ...

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