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
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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) | - |
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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SEE MORE:
COMPONENTS ILLUSTRATION *A w/ Woofer *B w/o Woofer *1 BACK DOOR CENTER GARNISH *2 BACK DOOR LOCK COVER *3 BACK DOOR SIDE GARNISH LH *4 BACK DOOR SIDE GARNISH RH *5 BACK DOOR TRIM BASE *6 BACK DOOR TRIM BOARD ASSEMBLY *7 POWER BACK DOOR WARNING BUZZER *
TERMINALS OF ECU HINT: Perform the inspection from the harness side with the connectors connected. STEERING HEATER AND VIBRATION ECU (a) Measure the voltage or resistance according to the value(s) in the table below. Terminal No. (Symbol) Terminal Description Condition Specified Condition
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