Code No.C1278: Valve power circuit stuck off (open circuit)

caution

If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table .).
Before replacing the ECU, ensure that the communication circuit is normal.

OPERATION

ABS-ECU contains the power supply circuit for the solenoid valve. The solenoid valve is energised by the valve relay, which is incorporated in ABS-ECU.
The valve relay, which is incorporated in ABS-ECU, is always energising the solenoid valve unless the initial check is in progress when the ignition switch is turned on, or the recurrent system check is in progress.
ABS-ECU activates the solenoid valve by turning on its driving transistor.

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes will be set under the cases below.

The solenoid valve relay monitor is "OFF" when the solenoid valve relay is "ON"

PROBABLE CAUSES

Damaged wiring harness or connector
ABS-ECU malfunction
Fuse malfunction