C0273

BRAKE CONTROL: ANTI-LOCK BRAKE SYSTEM: C0273/13: Open or Short Circuit in ABS Motor Relay Circuit

DTC C0273/13 - Open or Short Circuit in ABS Motor Relay Circuit

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

DESCRIPTION

The ABS motor relay supplies power to the ABS pump motor. While the ABS is activated, the ECU switches the motor relay on and operates the ABS pump motor.
If the voltage supplied to the motor relay (+BM) is below the DTCs detection threshold due to battery / generator shortage, the DTCs may be stored.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHOOSE DIAGNOSIS METHOD
(a) Choose the diagnosis method.

Method:





B -- INSPECT FUSE (ABS NO. 1)
A -- Continue to next step.
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (ABS MOTOR RELAY)
(a) Connect the intelligent tester to the DLC3.
(b) Start the engine.
(c) Select the tester menus: DIAGNOSTIC, OBD/MOBD, ABS/VSC and ACTIVE TEST.
(d) Read the ABS MOT RELAY status.






OK:
The operation sound of the ABS motor should be heard.
OK -- REPLACE BRAKE ACTUATOR ASSEMBLY
NG -- Continue to next step.
3. INSPECT FUSE (ABS NO. 1)





(a) Remove the ABS No. 1 fuse from the engine room relay block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
4. CHECK SKID CONTROL ECU CONNECTOR (+BM VOLTAGE)





(a) Disconnect the S1 skid control ECU connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
5. CHECK SKID CONTROL ECU CONNECTOR (GROUND)





(a) Disconnect the S1 skid control ECU connector.
(b) Measure the resistance of wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
6. RECONFIRM DTC
(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(b) Drive the vehicle at a speed of 6 km/h (4 mph) or more.
(c) Are the same DTCs recorded? Reading and Clearing Diagnostic Trouble Codes

HINT:
- The skid control ECU inspects the motor relay circuit when the stop light switch is turned off and the vehicle is running at a speed of 6 km/h (4 mph) or more.
- These DTCs may be recorded due to a malfunction in the connector terminal connection, etc.

NO -- END
YES -- REPLACE BRAKE ACTUATOR ASSEMBLY