Toyota Tacoma manuals

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

REPLACE MASTER CYLINDER SOLENOID

OK

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 ). (e) Check if the same DTCs are recorded. ).

(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:

Brake Switch "B" Circuit Short to Battery (P070312)
DESCRIPTION The purpose of this circuit is to prevent the engine from stalling while driving in lock-up when the brakes are suddenly applied. When the brake pedal is depressed, this switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in p ...

Automatic Disconnecting Differential Motor Limit Switch Circuit (P17A4)
DESCRIPTION When the A.D.D. actuator switches between 2WD and 4WD, the DL1 and DL2 terminals of the limit switch and ADD terminal of the A.D.D. position switch change to one of the following ON/OFF combinations listed in the table below. Terminal In 2WD Switchi ...

On-vehicle Inspection
ON-VEHICLE INSPECTION PROCEDURE 1. INSPECT CAMSHAFT TIMING GEAR BOLT (a) Remove the camshaft timing oil control solenoid assembly (See page ). (b) Check that the plunger strokes when the plunger in the center of the camshaft timing gear bolt is pressed. Standard stroke: 4 ...

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