ABS (Antilock Brake System)

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

DTC C0273/13 - Open 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 / alternator shortage, the DTCs may be stored.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST BY TECHSTREAM (ABS MOTOR RELAY)
(a) Connect Techstream to the DLC3.
(b) Start the engine.
(c) Select the Active Test mode on Techstream.
(d) Check the operation sound of the ABS motor individually when operating it with Techstream.

ABS / VSC / TRAC:





OK:
The operation sound of the ABS motor should be heard.
NG -- INSPECT ABS NO. 2 FUSE
OK -- REPLACE BRAKE ACTUATOR ASSEMBLY
2. INSPECT ABS NO. 2 FUSE





(a) Remove the ABS No. 2 fuse from the engine room R/B.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPLACE ABS NO. 2 FUSE
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (+BM TERMINAL)





(a) Disconnect the skid control ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BM CIRCUIT)
OK -- Continue to next step.
4. INSPECT SKID CONTROL ECU (GND TERMINAL)





(a) Disconnect the skid control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
5. RECONFIRM DTC
(a) Clear the DTCs (ABS (Antilock Brake System)).
(b) Drive the vehicle at a speed of 4 mph (6 km/h) or more.
(c) Are the same DTCs recorded? (ABS (Antilock Brake System))

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 4 mph (6 km/h) or more.

NO -- END
YES -- REPLACE BRAKE ACTUATOR ASSEMBLY