DTC C1257: Power Supply Drive Circuit [11/2018 - 12/2021]: 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)	-

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)