Lexus IS250 IS220d GSE20 ALE20 - BRAKE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

PERFORM ACTIVE TEST BY INTELLIGENT TESTER (ABS MOTOR RELAY)

INSPECT BRAKE ACTUATOR ASSEMBLY (GND TERMINAL)

RECONFIRM DTC

DTC C1251/51 Open in Pump Motor Circuit

DESCRIPTION

DTC No.DTC Detection ConditionTrouble Area
C1251/51
Actuator pump motor does not operate properly.
Open in actuator pump motor circuit continues for at least 2 seconds.
Brake actuator assembly (GND circuit)
Brake actuator assembly (Motor circuit)
Skid control ECU

WIRING DIAGRAM

Dtc C1251/51  Open In Pump Motor Circuit. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • NOTICE:
  • When replacing the skid control ECU, perform zero point calibration and store system information .
  • HINT:
  • When C0273/13, C0274/14 or C1361/91 is output together with C1251/51, inspect and repair the trouble areas indicated by C0273/13, C0274/14 or C1361/91 first.
1.PERFORM ACTIVE TEST BY INTELLIGENT TESTER (ABS MOTOR RELAY)

Connect the intelligent tester to the DLC3.

Start the engine.

Select the Active Test mode on the intelligent tester.

Check the operating sound of the ABS motor relay and motor when operating the motor relay with the intelligent tester.

ABS / VSC:
Item (Display)Vehicle Condition / Test DetailsDiagnostic Note
Motor Relay Turns ABS motor relay ON / OFF Operating sound of relay (clicking sound) and motor can be heard
  • OK:
  • The operating sound of the ABS motor relay and motor can be heard.
OK
Go to step 3
NG
2.INSPECT BRAKE ACTUATOR ASSEMBLY (GND TERMINAL)
Dtc C1251/51  Open In Pump Motor Circuit. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

Disconnect the brake actuator connector.

Measure the resistance according to the value(s) in the table below.

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    A13-1 (GND2) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK
3.RECONFIRM DTC

Reconnect the brake actuator connector.

Clear the DTC .

Start the engine.

Drive the vehicle at the speed of 4.3 mph (7 km/h) or more.

Check if the same DTC is recorded .

  • Result:
  • ConditionProceed to
    DTC (C1251/51) is not outputA
    DTC (C1251/51) is outputB
  • HINT:
If a speed signal of 4 mph (6 km/h) or more is input to the skid control ECU with the engine switch on (IG) and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
If a normal system code is output (trouble code is not output), slightly jiggle the connectors, wire harness, and fuses of the brake actuator assembly. Make sure that no DTCs are output.
If any DTCs are output while jiggling a connector or wire harness of the brake actuator assembly, inspect and repair the connector or wire harness.
B
REPLACE SKID CONTROL ECU
A
USE SIMULATION METHOD TO CHECK