DTC C1257: Power Supply Drive Circuit [06/2018 - ]: Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 300h, 2023 Lexus ES 300h, 2022 Lexus ES 300h, 2021 Lexus ES 300h, and 2020 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

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	MIL	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)	Does not come on	Electronically controlled brake system DTC

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

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)

Does not come on

Electronically controlled brake system DTC