Lexus IS250 IS220d GSE20 ALE20 - BRAKE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT ECU-IG RH FUSE

CHECK BATTERY

INSPECT SKID CONTROL ECU (IG1 TERMINAL)

INSPECT SKID CONTROL ECU (GND TERMINAL)

RECONFIRM DTC

DTC C1241/41 Low Battery Positive Voltage

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU (housed in the actuator assembly) outputs the DTC and prohibits operation with the fail safe function.


This DTC is stored when the IG1 terminal voltage deviates from the DTC detecting condition due to a malfunction in the power supply or charging circuit such as the battery or alternator circuit, etc.


The DTC is cancelled when the IG1 terminal voltage returns to normal.

DTC No.DTC Detection ConditionTrouble Area
C1241/41When any of the following is detected:
At a vehicle speed of 2 mph (3 km/h) or more, the IG1 terminal voltage is 9.5 V or less for 10 seconds or more.
When the solenoid relay remains ON and the IG1 terminal voltage is 9.5 V or less, the relay contact is open for 0.2 seconds or more.
With the IG1 terminal voltage 9.5 V or less, the vehicle speed sensor power supply decreases for 60 seconds or more.
Battery
Charging system
Power source circuit
Internal power supply circuit of the skid control ECU

WIRING DIAGRAM

Dtc C1241/41 Low Battery Positive Voltage. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • NOTICE:
  • When replacing the brake actuator assembly, perform zero point calibration .
1.INSPECT ECU-IG RH FUSE
Dtc C1241/41 Low Battery Positive Voltage. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Remove the ECU-IG RH fuse from the main body ECU RH.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    ECU-IG RH (10A) fuseAlwaysBelow 1 Ω
NG
REPLACE ECU-IG RH FUSE
OK
2.CHECK BATTERY

Install the ECU-IG RH fuse.

Check the battery voltage.

  • Standard voltage:
  • 10 to 14 V
NG
CHECK AND REPLACE CHARGING SYSTEM OR BATTERY
OK
3.INSPECT SKID CONTROL ECU (IG1 TERMINAL)
Dtc C1241/41 Low Battery Positive Voltage. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the skid control ECU connector.

Turn the engine switch on (IG).

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    A14-46 (IG1) - Body groundEngine switch on (IG)10 to 14 V
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK
4.INSPECT SKID CONTROL ECU (GND TERMINAL)
Dtc C1241/41 Low Battery Positive Voltage. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    A14-32 (GND1) - Body groundAlwaysBelow 1 Ω
    A14-1 (GND2) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK
5.RECONFIRM DTC

Reconnect the skid control ECU connector.

Clear the DTC .

Turn the engine switch on (IG).

Check if the same DTC is recorded .

  • Result:
  • ConditionProceed to
    DTC (C1241/41) is not outputA
    DTC (C1241/41) is outputB
  • HINT:
  • If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step .
B
REPLACE BRAKE ACTUATOR ASSEMBLY
A
USE SIMULATION METHOD TO CHECK
LEXUS IS250, IS220d / GSE20 ALE20
BRAKE CONTROL
Lexus IS250 IS220d GSE20 ALE20
VEHICLE STABILITY CONTROL SYSTEM w/o VDIM