Toyota Tacoma 2015-2018 Service Manual: Power Supply Drive Circuit (C1257)
DESCRIPTION
The motor relay (semiconductor relay) is built into the hydraulic brake booster and drives the pump motor based on a signal from the skid control ECU (master cylinder solenoid).
|
DTC No. |
DTC Detecting Condition |
Trouble Areas |
|---|---|---|
|
C1257 |
Open in pump motor input circuit |
Hydraulic brake booster pump motor circuit |
PROCEDURE
|
1. |
CHECK HYDRAULIC BRAKE BOOSTER PUMP MOTOR OPERATION |
(a) Turn the ignition switch to OFF.
(b) Disconnect the actuator connector (S1).
(c) Depress the brake pedal more than 20 times.
(d) Turn the ignition switch to the ON position.
(e) Check the hydraulic brake booster pump motor operation.
OK:
Hydraulic brake booster pump operates.
| NG | .gif) |
REPLACE MASTER CYLINDER SOLENOID |
|
.gif)
|
2. |
RECONFIRM DTC |
(a) Turn the ignition switch to OFF.
(b) Reconnect the actuator connector (S1).
(c) Turn the ignition switch to the ON position.
(d) Clear the DTCs (See page .gif)
).
(e) Check if the same DTCs are recorded.
|
Result |
Proceed to |
|---|---|
|
DTC output |
A |
|
DTC not output |
B |
| A | |
REPLACE MASTER CYLINDER SOLENOID |
| B | |
END |
Accumulator Low Pressure (C1256)
DESCRIPTION
The accumulator pressure sensor is connected to the skid control ECU in the master
cylinder solenoid.
DTC No.
DTC Detecting Condition
Trouble Areas
...
Transfer L4 Position Switch Circuit (C1268)
DESCRIPTION
A-TRAC is activated if wheel skid is detected while the transfer is in the L4
position.
DTC Code
DTC Detecting Condition
Trouble Areas
...
Other materials:
Clutch Release Cylinder(for R156f)
Components
COMPONENTS
ILLUSTRATION
Removal
REMOVAL
PROCEDURE
1. DRAIN CLUTCH FLUID
2. REMOVE FRONT PROPELLER SHAFT ASSEMBLY
(See page )
3. DISCONNECT CLUTCH RELEASE CYLINDER TO FLEXIBLE HOSE TUBE
(a) Using a union nut wrench, disconnect the clutch release cylinder
to ...
Driving assist systems
To help enhance driving safety and performance, the following systems operate
automatically in response to various driving situations.
Be aware, however, that these systems are supplementary and should not be relied
upon too heavily when operating the vehicle.
■ ABS (Anti-lock Brake Syst ...
On-vehicle Inspection
ON-VEHICLE INSPECTION
PROCEDURE
1. INSPECT REFRIGERANT PRESSURE
(a) This method uses a refrigerant recovery unit set to locate problem areas.
Read the refrigerant pressure when the test conditions are established.
Test conditions:
Temperature at the air inlet with the air recirculation ...