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 turns 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 low voltage from the battery/alternator, the DTCs may be stored.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (ABS 1 FUSE)
(a) Remove the ABS 1 fuse from the FL block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSE (ABS 1 FUSE)
OK -- Continue to next step.
2. INSPECT SKID CONTROL ECU (+BM TERMINAL VOLTAGE)





(a) Install the ABS 1 fuse.
(b) Disconnect the skid control ECU connector.
(c) 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.
3. INSPECT SKID CONTROL ECU (GND TERMINAL CONTINUITY)





(a) 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.
4. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY)
(a) Reconnect the skid control ECU connector.
(b) Connect Techstream to the DLC3.
(c) Turn the ignition switch to the ON position and turn the Techstream main switch on.
(d) Start the engine.
(e) Select the Active Test mode on Techstream.

ABS / VSC / TRAC:





(f) Check operating sound of the ABS motor when operating it with Techstream.
OK:
The operating sound of the ABS motor is heard.
NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- Continue to next step.
5. RECONFIRM DTC
(a) Clear the DTCs .
(b) Start the engine.
(c) Drive the vehicle at the speed of 6 km/h (4 mph) or more.
(d) Check that the same DTCs are recorded .
HINT:
- Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.
- If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU, with the ignition switch on and the stop light switch off, the ECU performs self-diagnosis of the motor and solenoid circuits.

Result:





HINT:
- 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.
- If the normal system code is output, slightly jiggle the connectors, wire harnesses, and fuses of the brake actuator assembly. Make sure that no DTCs are output.
- These DTCs may be stored due to a malfunction in the connector terminal connection, etc.

B -- END
A -- REPLACE BRAKE ACTUATOR ASSEMBLY