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:
Unable to Unlock Steering Wheel (Engine cannot Start)
DESCRIPTION
The steering lock actuator assembly activates the steering lock motor and moves
the lock bar into the steering column to lock the steering.
The steering may not unlock when the lock bar gets stuck in the lock hole of
the steering column. In this case, if the engine switch is turned ...
Disassembly
DISASSEMBLY
PROCEDURE
1. FIX VANE PUMP
(a) Using SST, fix the vane pump assembly in a vise.
SST: 09630-00014
09631-00132
NOTICE:
When using a vise, do not overtighten it.
2. REMOVE VANE PUMP OIL RESERVOIR SUB-ASSEMBLY
(a) Remove the 3 bolts and vane pump oil reservoir.
(b) Remove the O-r ...
Clutch Switch Circuit
DESCRIPTION
Clutch switch circuit inspection is necessary for manual transmission vehicles.
When the clutch pedal is released, the ECM receives the positive (+) battery
voltage through the ECU-IG NO. 2 fuse and ignition switch. While the clutch pedal
is depressed, the clutch switch assembly se ...
