Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

Description

Wiring diagram

Inspection procedure

INSPECT ABS1 FUSE

INSPECT ABS MOTOR2 RELAY

INSPECT ABS MOTOR1 (FAIL SAFE) RELAY

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

INSPECT ENGINE ROOM NO. 3 RELAY BLOCK

INSPECT BRAKE ACTUATOR ASSEMBLY

CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - ENGINE ROOM NO. 3 RELAY BLOCK)

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR ASSEMBLY)

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

RECONFIRM DTC

DTC C0273/13 Open in ABS Motor Relay Circuit

DTC C0274/14 Short to B+ in ABS Motor Relay Circuit

DTC C1361/91 Short Circuit in ABS Motor Fail Safe Relay Circuit

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. ABS, BA, TRC, or VSC are in operation during initial check.
    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
  5. Skid control ECU
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
  5. Skid control ECU
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
  5. Skid control ECU

Wiring diagram

Wiring diagram. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

Inspection procedure

NOTICE:

When replacing the skid control ECU, perform zero point calibration and store system information .

 

1.INSPECT ABS1 FUSE

Remove the ABS1 fuse from the engine room. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. Remove the ABS1 fuse from the 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 (50 A) fuse Always Below 1 ?
  NG  
REPLACE ABS1 FUSE
 
OK  
   

2.INSPECT ABS MOTOR2 RELAY

Install the ABS1 fuse. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. 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 k? or higher
3 - 5 Apply B+ between terminals 1 and 2 Below 1 ?
  NG  
REPLACE ABS MOTOR2 RELAY
 
OK  
   

3.INSPECT ABS MOTOR1 (FAIL SAFE) RELAY

Remove the ABS MOTOR1. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. 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 k? or higher
3 - 5 Apply B+ between terminals 1 and 2 Below 1 ?
  NG  
REPLACE ABS MOTOR1 (FAIL SAFE) RELAY
 
OK  
   

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

Measure the voltage according to the value(s) in the table below. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. 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

Measure the resistance according to the value(s) in the table below. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. 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 1 - ABS MOTOR2 relay terminal 1 Always Below 1 ?
ABS MOTOR1 (fail safe) relay terminal 1 - Body ground Always 10 k? or higher
ABS MOTOR1 (fail safe) relay terminal 3 - ABS MOTOR2 relay terminal 5 Always Below 1 ?
ABS MOTOR1 (fail safe) relay terminal 3 - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE ENGINE ROOM NO. 3 RELAY BLOCK
 
OK  
   

6.INSPECT BRAKE ACTUATOR ASSEMBLY

Disconnect the brake actuator connector. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. Disconnect the brake actuator connector.

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

Standard resistance:

Tester Connection Condition Specified Condition
2 (BM) - 30 (MT) Always 0.92 to 1.12 k?
  NG  
REPLACE BRAKE ACTUATOR ASSEMBLY
 
OK  
   

7.CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - ENGINE ROOM NO. 3 RELAY BLOCK)

Measure the resistance according to the value(s) in the table below. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

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

Standard resistance:

Tester Connection Condition Specified Condition
A13-2 (BM) - ABS MOTOR2 relay terminal 3 Always Below 1 ?
A13-2 (BM) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

8.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR ASSEMBLY)

Disconnect the skid control ECU connector. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. 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
J78-15 (MT) - A13-30 (MT) Always Below 1 ?
J78-15 (MT) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

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

Disconnect the skid control ECU connector. Diagnostic code C0273 C0274 C1361ABS Motor Relay Circuit. Lexus IS250 IS220D

  1. Disconnect the skid control ECU connector.

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

Standard resistance:

LHD:

Tester Connection Condition Specified Condition
A35-3 (MR) - ABS MOTOR2 relay terminal 2 Always Below 1 ?
A35-3 (MR) - Body ground Always 10 k? or higher
A35-11 (R+) - ABS MOTOR1 (fail safe) relay terminal 1 Always Below 1 ?
A35-11 (R+) - Body ground Always 10 k? or higher
J78-1 (MRF) - ABS MOTOR1 (fail safe) relay terminal 2 Always Below 1 ?
J78-1 (MRF) - Body ground Always 10 k? or higher

RHD:

Tester Connection Condition Specified Condition
J98-3 (MR) - ABS MOTOR2 relay terminal 2 Always Below 1 ?
J98-3 (MR) - Body ground Always 10 k? or higher
J98-11 (R+) - ABS MOTOR1 (fail safe) relay terminal 1 Always Below 1 ?
J98-11 (R+) - Body ground Always 10 k? or higher
J78-1 (MRF) - ABS MOTOR1 (fail safe) relay terminal 2 Always Below 1 ?
J78-1 (MRF) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

10.RECONFIRM DTC

  1. Clear the DTC .

  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 .

HINT:

Reinstall the relays, connectors, etc. and restore the vehicle to the 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 skid control ECU and 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 skid control ECU and brake actuator assembly, inspect and repair the connector or wire harness.
  B  
REPLACE SKID CONTROL ECU
 
A  
   
USE SIMULATION METHOD TO CHECK