Power Supply Drive Circuit (C1257)
The motor relay (semiconductor relay) is built into the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU.
DTC Code | DTC Detection Condition | Trouble Area |
|---|---|---|
C1257 |
There is an open in the motor system circuit (motor input circuit). |
Master cylinder solenoid (Skid control ECU) |
NOTICE:
When replacing the master cylinder solenoid, perform calibration (See page .gif)
).
PROCEDURE
CHECK PUMP MOTOR OPERATION
(a) Turn the ignition switch off.
(b) Disconnect the A6 skid control ECU connector.
(c) Depress the brake pedal more than 40 times.
(d) Turn the ignition switch to ON.
(e) Check pump motor operation.
OK:
Pump motor operates normally.
| NG | .gif) | REPLACE MASTER CYLINDER SOLENOID |
|
.gif)
RECONFIRM DTC
(a) Turn the ignition switch off.
(b) Reconnect the A6 skid control ECU connector.
(c) Turn the ignition switch to ON.
(d) Clear the DTCs (See page ).
(e) Turn the ignition switch off.
(f) Check if the same DTC is output (See page
).
Result | Proceed to |
|---|---|
DTC is output |
A |
DTC is not output |
B |
| A | | REPLACE MASTER CYLINDER SOLENOID |
| B | | USE SIMULATION METHOD TO CHECK |
Test yourself
A quick Toyota 4Runner quiz: every answer comes with an explanation and a link to the manual page.