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:
Cruise Main Indicator Light Circuit
DESCRIPTION
When the ECM detects a cruise control switch on signal from the cruise
control switch, the ECM sends the signal to the combination meter assembly
through CAN communication. Then the cruise control indicator light turns
on.
The cruise control indicator light circui ...
Pressure Control Solenoid "D" Performance (Shift Solenoid Valve SLT) (P2714)
SYSTEM DESCRIPTION
The shift solenoid valve SLT controls the transmission line pressure for smooth
transmission operation based on signals from the throttle position sensor and the
vehicle speed sensor. The ECM adjusts the current to shift solenoid valve SLT to
control hydraulic line pressure ...
Terminals Of Ecu
TERMINALS OF ECU
1. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND DRIVER SIDE JUNCTION
BLOCK
(a) Disconnect the main body ECU (multiplex network body ECU) connectors.
Text in Illustration
*1
Main Body ECU (Multiplex Network Body ECU)
-
-
...
