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 |
| Skid control ECU (Brake booster with master cylinder assembly) | - |
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.
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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
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HV Control System Regenerative Malfunction (C1259,C1310)
DESCRIPTION The skid control ECU (brake booster with master cylinder assembly) communicates with the hybrid vehicle control ECU and controls braking force according to the motor's regenerative force.
Low Output Signal of Front Speed Sensor RH (C1271,C1272,C1464,C1465)
DESCRIPTION Each speed sensor detects the wheel speed and sends the signals to the skid control ECU (brake booster with master cylinder assembly). These signals are used for ABS control. DTCs C1271 an
Low Output Signal of Rear Speed Sensor RH (C1273,C1274,C1466,C1467)
DESCRIPTION Each speed sensor detects the wheel speed and sends the signals to the skid control ECU (brake booster with master cylinder assembly). These signals are used for ABS control. DTCs C1273 an
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Removal
REMOVAL CAUTION / NOTICE / HINT NOTICE: While the auxiliary battery is connected, even if the power switch is off, the brake control system activates when the brake pedal is depressed or any door courtesy switch turns on. Therefore, when servicing the brake system components, do not operate the brak
Diagnosis System
DIAGNOSIS SYSTEM CHECK DLC3 (a) Check the DLC3. Click here INSPECT AUXILIARY BATTERY VOLTAGE (a) Measure the auxiliary battery voltage. Standard voltage: 11 to 14 V (power switch off) If the voltage is below 11 V, recharge or replace the auxiliary battery.
