Toyota 4Runner: Open in Pump Motor Circuit (C1251)

DESCRIPTION

The motor relay (semiconductor relay) is built into the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU.

CAUTION / NOTICE / HINT

NOTICE:

When replacing the master cylinder solenoid, perform calibration (See page ).

HINT:

Remove the hydraulic brake booster assembly before the inspection (See page ).

PROCEDURE

(a) Remove the hydraulic brake booster assembly (See page ).

(b) Check the tightening torque of the 2 screws which secure the wire harness connecting the master cylinder solenoid and brake booster with accumulator pump assembly (See page ).

OK:

The harness is tightened to the specified torque.

Torque:

2.9 N·m {30 kgf·cm, 26 in·lbf}

NG

RETIGHTEN SCREWS

OK

(a) Using a screwdriver, remove the 2 screws and pull out the wire harness from the master cylinder solenoid.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition Red wire terminal - Black wire terminal Always Below 2 Ω Text in Illustration *1 Pump motor wire harness *a Red wire *b Black wire

NG

REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

OK

(a) Reassemble the hydraulic brake booster assembly (See page ).

(b) Install the hydraulic brake booster assembly (See page ).

(c) Clear the DTCs (See page ).

(d) Turn the ignition switch off.

(e) Check if the same DTC is output (See page
).

A

REPLACE MASTER CYLINDER SOLENOID

B

USE SIMULATION METHOD TO CHECK