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:
Invalid Data Received from Vehicle Dynamics Control Module (U0416)
DESCRIPTION
This DTC is detected if a wheel speed malfunction signal is sent from the skid
control ECU (brake actuator assembly).
DTC No.
Detection Item
DTC Detection Condition
Trouble Area
U0416
Invalid Data Received From V ...
Removal
REMOVAL
PROCEDURE
1. REMOVE ROOF HEADLINING ASSEMBLY (for LED Type Stop Light)
for Double Cab:
(See page
)
for Access Cab:
(See page
)
2. REMOVE CENTER STOP LIGHT ASSEMBLY (for Bulb Type Stop Light)
(a) Apply protective tape around the center stop light as ...
Terminals Of Ecu
TERMINALS OF ECU
1. NAVIGATION RECEIVER ASSEMBLY
Terminal No. (Symbols)
Wiring Color
Terminal Description
Condition
Specified Condition
N19-3 (ACC2) - N24-7 (GND1)*3
Y - W-B
Power source (ACC)
...
