Toyota 4Runner: Brake Booster Pump Motor on Time Abnormally Long (C1252)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Brake Booster Pump Motor on Time Abnormally Long (C1252)

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.

DTC Code	DTC Detection Condition	Trouble Area
C1252	The motor operates for 3 minutes or more.	Brake booster with accumulator pump assembly Pump motor wire harness condition Master cylinder solenoid (Skid control ECU) Hydraulic brake booster assembly

HINT:

The pump motor continues operation for the first 3 minutes, and then starts and stops repeatedly.

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

When DTC C1253, C1254, C1256 or C1452 is output together with DTC C1252, inspect and repair the trouble area indicated by DTC C1253, C1254, C1256 or C1452 first.

PROCEDURE

1.	CHECK PUMP MOTOR OPERATION

(a) Turn the ignition switch off.

(b) Depress the brake pedal more than 40 times.

(d) Check how the pump motor operates.

Result

Result	Proceed to
Pump motor does not operate	A
Pump motor operates continuously and does not stop	B
Pump motor operates intermittently	C
Pump motor operates, and then stops	D

REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

GO TO STEP 4

GO TO STEP 5

2.	CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

RETIGHTEN SCREWS

3.	CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS

REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

4.	READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Accumulator Sensor	Accumulator pressure sensor reading/ Min.: 0.00 V, Max.: 5.00 V	3.58 to 5 V	If the value is constant regardless of the pump operation, an accumulator pressure sensor malfunction is suspected.

(f) Check the accumulator output value.

Result

Result	Proceed to
Output value is within "Normal Condition" range	A
Output value is out of "Normal Condition" range	B
Output value is constant regardless of pump operation	C

REPLACE MASTER CYLINDER SOLENOID

REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

5.	RECONFIRM DTC

(a) Clear the DTCs (See page ).

(b) Turn the ignition switch off.

(d) Wait for more than 5 minutes.

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

HINT:

Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result

Result	Proceed to
DTC is output	A
DTC is not output	B

REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

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. DTC Code D ...

Pump Motor Relay (C1253)

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. DTC Code D ...

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