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Home >> Lexus >> 2020 >> LC 500 >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (Coupe) (2 Of 4) >> Electronically Controlled Brake System >> DTC C1256/57: Accumulator Low Pressure [03/2017 - 09/2018] >> Description

DTC C1256/57: Accumulator Low Pressure [03/2017 - 09/2018]: Description

The accumulator pressure sensor is built into the brake actuator assembly and detects the accumulator pressure.

The skid control ECU assembly turns on the brake warning light / yellow (minor malfunction), and sounds the meter buzzer if it senses a decrease in the accumulator pressure.

DTC C1256/57 may be stored if the accumulator pressure drops due to frequent braking (this is not a malfunction).

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1256/57 Accumulator Low Pressure 141
143
  • INF Code: 141
    • Either of the following is detected:
      1. When inputting the vehicle speed, the brake operation is input with the accumulator pressure low or the accumulator pressure extremely decreased while braking for 0.3 seconds or more.
      2. The accumulator pressure has been low since system start and pressure is less than 14.62 MPa (149.1 kgf/cm2 , 2121 psi) for 120 seconds or more.

        (Stores the DTC after the conditions are met, and sounds buzzer.)

  • INF Code: 143
    • Any of the following is detected:
      1. When inputting the vehicle speed, any of the wheel cylinder pressure sensor values is lower than the specified value with the accumulator pressure low for 0.5 seconds or more.
      2. The accumulator pressure decreased without increasing the wheel cylinder pressure of each wheel.
      3. With the ABS motor relay abnormal or off, the accumulator pressure is less than 14.62 MPa (149.1 kgf/cm2 , 2121 psi) for 0.5 seconds or more.
  • INF Code: 141
    • Accumulator pressure dropped due to frequent brake pedal operation (not a malfunction)
    • Pump motor malfunction
    • Accumulator deterioration
    • Brake fluid leaks
    • Accumulator pressure sensor
    • Supply voltage reduced
  • INF Code: 143
    • Accumulator pressure dropped due to frequent brake pedal operation (not a malfunction)
    • Pump motor malfunction
    • Accumulator deterioration
    • Accumulator pressure sensor
    • Supply voltage reduced
 Electronically controlled brake system DTC
DTC No. Brake warning light / yellow (minor malfunction) code ABS warning light code Slip indicator light code Brake hold standby indicator light code
C1256 57 42 45 21
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