ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1257

DTC Code	DTC Name
C1257	Power Supply Drive Circuit

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 After hard pump motor operation, when the accumulator pressure is less than 15.3 MPa (156 kgf/cm², 2219 psi), the pump motor does not operate for 1 second or more. INF Code: 362 When a motor relay drive test is being performed, one or both motor relays do not operate for 0.2 seconds or more.	Skid control ECU (brake booster with master cylinder assembly)	Electronically controlled brake system DTC

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

Note

C1257

Power Supply Drive Circuit

361

362

INF Code: 361

After hard pump motor operation, when the accumulator pressure is less than 15.3 MPa (156 kgf/cm², 2219 psi), the pump motor does not operate for 1 second or more.

INF Code: 362

When a motor relay drive test is being performed, one or both motor relays do not operate for 0.2 seconds or more.

Skid control ECU (brake booster with master cylinder assembly)

Electronically controlled brake system DTC

CAUTION / NOTICE / HINT

Note

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

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PROCEDURE

CHECK DTC

Clear the DTCs.

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Chassis > ABS/VSC/TRC > Clear DTCs
Turn the power switch off.
Turn the power switch on (IG).

Check if the same DTC is output.

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Chassis > ABS/VSC/TRC > Trouble Codes

Result

Result	Proceed to
DTC C1257 is output.	A
DTCs C1241, C1242 and/or C1253 are output.	B

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here