Lexus IS250 · Service Manual BRAKE

C1241/41

Diagnostic trouble codes

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 Condition
 Trouble Area
C1241/41
 When any of the following is detected:
  1. 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.
  2. 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.
  3. With the IG1 terminal voltage 9.5 V or less, the vehicle speed sensor power supply decreases for 60 seconds or more.
  1. Battery
  2. Charging system
  3. Power source circuit
  4. Internal power supply circuit of the skid control ECU

WIRING DIAGRAM

C109390E02

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration (Click here).


1. INSPECT ECU-IG RH FUSE

  1. C106592E04
    Remove the ECU-IG RH fuse from the main body ECU RH.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    ECU-IG RH (10A) fuse
    		 Always
    		 Below 1 Ω



NG
REPLACE ECU-IG RH FUSE
OK


2. CHECK BATTERY

  1. Install the ECU-IG RH fuse.

  1. 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)

  1. F049362E29
    Disconnect the skid control ECU connector.

  1. Turn the engine switch on (IG).

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    A14-46 (IG1) - Body ground
    		 Engine switch on (IG)
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK


4. INSPECT SKID CONTROL ECU (GND TERMINAL)

  1. F049362E31
    Turn the engine switch off.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    A14-32 (GND1) - Body ground
    		 Always
    		 Below 1 Ω
    A14-1 (GND2) - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK


5. RECONFIRM DTC

  1. Reconnect the skid control ECU connector.

  1. Clear the DTC (Click here).

  1. Turn the engine switch on (IG).

  1. Check if the same DTC is recorded (Click here).

    Result:
    Condition
    		 Proceed to
    DTC (C1241/41) is not output
    		 A
    DTC (C1241/41) is output
    		 B

    HINT:
    If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (Click here).



 B
REPLACE BRAKE ACTUATOR ASSEMBLY
A

USE SIMULATION METHOD TO CHECK


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