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:
Terminals Of Ecu
TERMINALS OF ECU
1. CHECK DRIVER SIDE JUNCTION BLOCK AND MAIN BODY ECU (MULTIPLEX NETWORK BODY
ECU)
(a) Disconnect the MB main body ECU (multiplex network body ECU) connectors.
(b) Measure the voltage and resistance according to the value(s) in the table
below.
HINT:
Measure the values on ...
Network Gateway Ecu
Components
COMPONENTS
ILLUSTRATION
Installation
INSTALLATION
PROCEDURE
1. INSTALL NETWORK GATEWAY ECU
(a) Install the network gateway ECU with the bolt.
Torque:
3.0 N·m {31 kgf·cm, 27 in·lbf}
(b) Connect the connector.
2. INSTALL LOWER INSTRUMENT PANEL ASSEMBLY
(See page )
R ...
AUTO LSD system
The AUTO LSD system aids traction by using the traction control system to control
engine performance and braking when one of the rear wheels begins to spin.
The system should be used only when one of the rear wheels spinning occurs in
a ditch or rough surface.
■ System operation
The sys ...
