Diagnostic trouble code C1254 Land Cruiser

DESCRIPTION

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER SENSOR)

RECONFIRM DTC

DTC C1254/54 Pressure Switch Circuit

Description

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

Diagnostic trouble code C1254 Land Cruiser Description
DTC Code DTC Detection Condition Trouble Area
C1254/54 There is an accumulator pressure sensor malfunction (the fluid pressure does not change when the pump operates or when the brake is applied).
  1. Hydraulic brake booster
  2. Accumulator pressure sensor
  3. Master cylinder pressure sensor

Inspection procedure

NOTICE:

When replacing the master cylinder solenoid, perform zero point calibration .

1.READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

  1. Turn the ignition switch off.

  1. Connect the intelligent tester to the DLC3.

  1. Depress the brake pedal more than 20 times.

  1. Turn the ignition switch to ON and turn the intelligent tester on.

  1. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    ABS/VSC/TRC
    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.

  1. Check the accumulator output value.

    Result
    Result Proceed to
    Output value is within the "Normal Condition" range A
    Output value is out of the "Normal Condition" range LHD B
    Output value is constant regardless of pump operation LHD
    Output value is out of the "Normal Condition" range RHD C
    Output value is constant regardless of pump operation RHD
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   

2.READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER SENSOR)

  1. Turn the ignition switch off.

  1. Depress the brake pedal more than 20 times.

  1. Install the brake pedal effort gauge (SST), and bleed air.

SST

09709-29018

  1. Turn the ignition switch to ON and turn the intelligent tester on.

  1. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    ABS/VSC/TRC
    Tester Display Measurement Item/Range Normal Condition Diagnostic Note
    Master Cylinder Sensor Master cylinder pressure sensor reading / min.: 0.00 V, max.: 5.00 V 0.3 to 1.8 V With pedal effort of 49 N (5 kgf, 11 in.*lbf) The front brake pressure is 930 to 2130 kPa (9.5 to 21.7 kgf/cm2, 135 to 309 psi).

  1. Check that the master cylinder pressure sensor output value is normal.

    OK:

    Master cylinder pressure sensor value is normal.

    Result
    Result Proceed to
    OK A
    NG LHD B
    RHD C
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   

3.RECONFIRM DTC

  1. Clear the DTC .

  1. Turn the ignition switch off.

  1. Depress the brake pedal more than 20 times.

  1. Turn the ignition switch to ON.

  1. Wait until the pump motor stops.

  1. Depress the brake pedal and release it.

  1. Wait for 25 minutes.

  1. Check if the same DTC is output .

    Result
    Result Proceed to
    DTC is not output A
    DTC is output LHD B
    RHD C
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   
USE SIMULATION METHOD TO CHECK