Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000001A6A007X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1251/51; Open in Pump Motor Circuit; 2007 MY LX470 [08/2006 -        ]

DTC

C1251/51

Open in Pump Motor Circuit

DESCRIPTION

DTC No.

DTC Detection Condition

Trouble Area

C1251/51

Either of the following 1. or 2. is detected.

  1. After turning the ignition switch ON, the current of more than 30 A flows to the motor for more than 1 sec.
  2. After turning the ignition switch ON, less than 7 A change in current is detected more than 3 times in a row when the motor is ON.

Hydraulic brake booster pump motor

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK OPERATION BRAKE ACTUATOR PUMP MOTOR

(a) Disconnect 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 4

NG

2.

CHECK BRAKE ACTUATOR RESISTANCE

(a) Disconnect A43 and A44 actuator connectors.

(b) Measure the resistance between terminals MT+ and MT-, BM1 and MTT, BM2 and MTT, GND1 and MT+, GND2 and MT+ of the actuator.

Standard resistance:

Tester Connection

Specified Condition

A44-5 (MT+) - A44-8 (MT-)

30 to 36 Ω

A43-2 (BM1) - A44-7 (MTT)

30 to 36 Ω

A44-3 (BM2) - A44-7 (MTT)

30 to 36 Ω

A43-1 (GND1) - A44-5 (MT+)

30 to 36 Ω

A44-6 (GND2) - A44-5 (MT+)

30 to 36 Ω
NG

REPLACE BRAKE ACTUATOR

OK

3.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR (MT+, MT-))
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE SKID CONTROL ECU ASSEMBLY

4.

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

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

5.

CHECK BRAKE ACTUATOR PUMP MOTOR

(a) Check the brake actuator pump motor 2007 MY LX470 [08/2006 -        ]; BRAKE: HYDRAULIC BRAKE BOOSTER: DISASSEMBLY+ .

NG

REPLACE BRAKE ACTUATOR PUMP MOTOR

OK

REPLACE BRAKE ACTUATOR