Last Modified: 4-30-2014 6.6 C Doc ID: RM000001A6O002X
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1252/52; Brake Booster Pump Motor on Time Abnormally Long; 2006 MY LX470 [05/2005 -        ]

DTC

C1252/52

Brake Booster Pump Motor on Time Abnormally Long

DESCRIPTION

DTC No.

DTC Detection Condition

Trouble Area

C1252/52

After the ignition switch is turned ON, the power is supplied to the pump motor for more than 5 minutes.

  • Hydraulic brake booster pump motor
  • Hydraulic brake booster pump motor circuit
  • Pressure switch (PH or PL)

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK OPERATION OF BRAKE ACTUATOR PUMP MOTOR

(a) Disconnect the A43 and A44 actuator connectors.

(b) Connect the battery positive (+) lead to terminal 2 (BM1) or 3 (BM2) and battery negative (-) lead to terminal 1 (GND1) or 6 (GND2) of the brake actuator (pump motor).

OK:

Operation sound of pump motor should be heard.

OK

GO TO STEP 10

NG

2.

CHECK WIRE HARNESS (BRAKE ACTUATOR - ABS MTR 1 RELAY AND ABS MTR 2 RELAY)

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

3.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR)

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

4.

READ DATA LIST (PRESS SWITCH (PH) AND (PL))

(a) Check the DATA LIST for proper functioning of the hydraulic brake boost pressure switch (PH) and (PL).

(b) Depress the brake pedal more than 40 times with the ignition switch OFF. Then turn the ignition switch ON and check the pressure switch (PH) and (PL) condition.

Skid control ECU assembly:

Item

Measurement Item/Range (Display)

Normal Condition

Diagnostic Note

PRESS HIGH

HIGH Hydraulic brake boost pressure/ ON or OFF

-

-

PRESS LOW

LOW Hydraulic brake boost pressure/ ON or OFF

-

-

HINT:

When pressure in power supply system is released, reaction force becomes light.

OK:

"OFF" turns to "ON"

OK

REPLACE SKID CONTROL ECU ASSEMBLY

NG

5.

CHECK BRAKE BOOSTER PRESSURE SWITCH (PH)

(a) Disconnect the A43 actuator connector.

(b) With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

HINT:

When pressure in power supply system is released, reaction force becomes light.

(c) Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator connector.

Standard resistance:

0.9 to 1.1 kΩ

(d) Connect the A43 actuator connector.

(e) Disconnect the A43 actuator connector after the ignition switch has been ON and the pump motor has stopped.

(f) Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator.

Standard resistance:

Below 1 Ω

HINT:

After inspection, connect the connector and clear the DTC.

NG

REPLACE BRAKE ACTUATOR

OK

6.

CHECK BRAKE BOOSTER PRESSURE SWITCH (PL)

(a) Disconnect the A44 actuator connector.

(b) With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

HINT:

When pressure in power supply system is released, reaction force becomes light.

(c) Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator connector.

Standard resistance:

5.1 to 6.3 kΩ

(d) Connect the A44 actuator connector.

(e) Disconnect the A44 actuator connector after the ignition switch has been ON and the pump motor has stopped.

(f) Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator.

Standard resistance:

1.0 kΩ

HINT:

After inspection, connect the connector and clear the DTC.

NG

REPLACE BRAKE ACTUATOR

OK

7.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR (PRESSURE SWITCH))

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

8.

INSPECT RELAY (Marking: ABS MTR 1, ABS MTR 2)

(a) Remove the ABS MTR 1 and ABS MTR 2 from the engine room relay block.

(b) Measure the resistance of the relay.

Standard resistance:

Tester Connection

Specified Condition

1 - 2

10 kΩ or higher

1 - 2

Below 1 Ω

(When battery voltage is applied to terminals 3 and 4)

NG

REPLACE RELAY

OK

9.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - ABS MTR 1 RELAY AND ABS MTR 2 RELAY)

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE SKID CONTROL ECU ASSEMBLY

10.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR)

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

11.

CHECK BRAKE ACTUATOR PUMP MOTOR

(a) Check the brake actuator pump motor 2006 MY LX470 [05/2005 -        ]; BRAKE: HYDRAULIC BRAKE BOOSTER: DISASSEMBLY+ .

NG

REPLACE BRAKE ACTUATOR PUMP MOTOR

OK

REPLACE BRAKE ACTUATOR