DTC C1257/57: IG Power Source: Description
WARNING: This page is about a different car, the 2007 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
The motor relay (semiconductor relay) is built in the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU.
DTC DETECTION CONDITION TABLE
| DTC Code | DTC Detection Condition | Trouble Area |
|---|---|---|
| C1257/57 | Open in motor system circuit (motor input circuit). | Hydraulic brake booster pump motor circuit |