Lexus NX: Power Supply Drive Circuit (C1257)

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) detects a drop in accumulator pressure according to the signals from the accumulator pressure sensor, then operates and stops the motor relay as well as the pump motor.

The skid control ECU (brake booster with master cylinder assembly) troubleshoots the built-in motor relay drive circuit, and stores this DTC when a malfunction is detected.

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

Note

C1257

Power Supply Drive Circuit

361

362

  • INF Code: 361
    • While accumulator pressure falls below hard pump ON pressure, the hard drive circuit does not operate for 1 second or more.
  • INF Code: 362
    • When hard driving, one of the 3 built-in motor relays does not operate for 0.2 seconds or more.

Skid control ECU (Brake booster with master cylinder assembly)

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CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake booster with master cylinder assembly), perform initialization and calibration of the linear solenoid valve.

Click here

HINT:

When C1241, C1242 and/or C1253 are output together with C1257, inspect and repair the trouble areas indicated by C1241, C1242 and/or C1253 first.

for C1241 and C1242: Click here

for C1253: Click here

PROCEDURE

1.

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

(a) Replace the skid control ECU (brake booster with master cylinder assembly).

Click here

NEXT

END

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