Lexus IS250 · Service Manual BRAKE

C0273/13

Diagnostic trouble codes

DESCRIPTION

If a DTC of the motor line is stored, the ABS MOTOR1 (fail safe) relay cuts off the power supply to the ABS MOTOR2 relay and performs fail safe.
While any of the ABS, TRC, VSC, or BA is operating, the skid control ECU (housed in the actuator assembly) turns the ABS MOTOR2 relay on and activates the pump motor in the brake actuator.
This code may be stored if the motor relay (+BM) voltage becomes lower than the DTC detecting condition due to insufficient output from the battery or alternator.
DTC No.
 DTC Detection Condition
 Trouble Area
C0273/13
 When any of the following (1 or 2) is detected:
  1. All of the following conditions continue for 0.12 seconds or more.
    1. The IG1 terminal voltage is between 9.5 and 17.2 V.
    2. During initial check and ABS, BA, TRC, or VSC are in operation.
    3. Relay contact is open when the relay is ON.
  2. All of the following conditions continue for 0.12 seconds.
    1. The IG1 terminal voltage is 9.5 V or less.
    2. Relay contact remains open when the relay is ON.
  1. ABS1 fuse
  2. ABS MOTOR2 relay
  3. ABS MOTOR2 relay circuit
  4. Brake actuator assembly
C0274/14
 When the motor relay is OFF, the ABS MOTOR2 relay remains closed for 4 seconds or more.
  1. ABS1 fuse
  2. ABS MOTOR2 relay
  3. ABS MOTOR2 relay circuit
  4. Brake actuator assembly
C1361/91
 Immediately after the engine switch is turned on (IG), the relay contact is closed for 4 seconds when the ABS MOTOR1 (fail safe) relay is OFF.
  1. ABS1 fuse
  2. ABS MOTOR1 (fail safe) relay
  3. ABS MOTOR1 (fail safe) relay circuit
  4. Brake actuator assembly

WIRING DIAGRAM

C109434E01

INSPECTION PROCEDURE

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


1. INSPECT ABS1 FUSE

  1. C109429E01
    Remove the ABS1 fuse from engine room No. 1 R/B.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    ABS1 (50A) fuse
    		 Always
    		 Below 1 Ω



NG
REPLACE ABS1 FUSE
OK


2. INSPECT ABS MOTOR2 RELAY

  1. F050240E04
    Install the ABS1 fuse.

  1. Remove the ABS MOTOR2 relay.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    3 - 5
    		 Always
    		 10 kΩ or higher
    3 - 5
    		 Apply B+ between terminals 1 and 2
    		 Below 1 Ω



NG
REPLACE ABS MOTOR2 RELAY
OK


3. INSPECT ABS MOTOR1 (FAIL SAFE) RELAY

  1. F050241E07
    Remove the ABS MOTOR1 (fail safe) relay.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    3 - 5
    		 Always
    		 10 kΩ or higher
    3 - 5
    		 Apply B+ between terminals 1 and 2
    		 Below 1 Ω



NG
REPLACE ABS MOTOR1 (FAIL SAFE) RELAY
OK


4. INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL)

  1. C106593E08
    Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    ABS MOTOR1 (fail safe) relay terminal 5 - Body ground
    		 Always
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK


5. INSPECT ENGINE ROOM NO. 3 RELAY BLOCK

  1. C106593E09
    Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    ABS MOTOR1 (fail safe) relay terminal 3 - ABS MOTOR2 relay terminal 5
    		 Always
    		 Below 1 Ω
    ABS MOTOR1 (fail safe) relay terminal 3 - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPAIR OR REPLACE ENGINE ROOM NO. 3 RELAY BLOCK
OK


6. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 3 RELAY BLOCK)

  1. C110920E04
    Disconnect the skid control ECU connector.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    A14-2 (BM) - ABS MOTOR2 relay terminal 3
    		 Always
    		 Below 1 Ω
    A14-2 (BM) - Body ground
    		 Always
    		 10 kΩ or higher
    A14-14 (MRF) - ABS MOTOR1 (fail safe) relay terminal 2
    		 Always
    		 Below 1 Ω
    A14-14 (MRF) - Body ground
    		 Always
    		 10 kΩ or higher
    A14-15 (MR) - ABS MOTOR2 relay terminal 2
    		 Always
    		 Below 1 Ω
    A14-15 (MR) - Body ground
    		 Always
    		 10 kΩ or higher
    A14-45 (R+) - ABS MOTOR1 (fail safe) relay terminal 1
    		 Always
    		 Below 1 Ω
    A14-45 (R+) - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


7. RECONFIRM DTC

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Drive the vehicle at the speed of 4 mph (6 km/h) or more.

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

    HINT:
    Reinstall the relays, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.


    Result:
    Condition
    		 Proceed to
    DTCs (C0273/13, C0274/14 and/or C1361/91) are not output
    		 A
    DTCs (C0273/13, C0274/14 and/or C1361/91) are output
    		 B

    HINT:
    1. 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.
    2. If the normal system code is output (the 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.
    3. If any DTCs are output while jiggling a connector or wire harness of the brake actuator (skid control ECU), inspect and repair the connector or wire harness.



 B
REPLACE BRAKE ACTUATOR ASSEMBLY
A

USE SIMULATION METHOD TO CHECK


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