C1253

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1252/52,C1253/53: Brake Booster Pump Motor on Time Abnormally Long


DESCRIPTION

The skid control ECU detects decreases in the accumulator pressure according to the data from the accumulator pressure sensor, and then starts and stops the pump motor by operating the motor relay.

The skid control ECU usually drives the motor (ABS MOTOR1) relay 1 for Electronically Controlled Brake System control, and the motor (ABS MOTOR2) relay 2 for ABS control. If either is of them malfunctioning, the other will substitute.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU or brake actuator assembly, perform initialization of linear solenoid valve and calibration Initialization.

PROCEDURE

1. INSPECT FUSE (ABS1, ABS2 AND ABS MOTOR FUSES)

(a) Remove the ABS1, ABS2 and ABS MOTOR fuses from the engine room R/B (J/B) No.1.

(b) Check the ABS1, ABS2 and ABS MOTOR fuses.

Resistance:

Below 1 Ohms (Continuity)

NG -- REPLACE FUSE (ABS1, ABS2 OR ABS MOTOR FUSE)
OK -- Continue to next step.

2. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Select the Active Test mode on the Techstream.

ABS / VSC / TRAC:





(d) *: Electronically Control Brake

(e) Check the operation sound of the ABS motor relay and motor when operating it with the Techstream.

OK:

The operation sound of the ABS motor relay and motor is heard.

NG -- INSPECT ABS MOTOR RELAY
OK -- Continue to next step.

3. INSPECT BRAKE ACTUATOR ASSEMBLY

(a) Disconnect the brake actuator assembly connector.





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

Resistance:





NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO BRAKE ACTUATOR ASSEMBLY)

(a) Disconnect the skid control ECU connector and brake actuator assembly connector.





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

Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Select the Data List mode on the Techstream.

ABS / VSC / TRAC:





(d) Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the Techstream with the motor stopped (not braking).

OK:

Accumulator pressure sensor voltage does not drop.

NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- Continue to next step.

6. INSPECT ABS MOTOR RELAY

(a) Remove the ABS MOTOR1 relay and ABS MOTOR2 relay.





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

Resistance:





NG -- REPLACE ABS MOTOR RELAY
OK -- Continue to next step.

7. INSPECT ABS MOTOR RELAY (POWER SOURCE TERMINAL)

(a) Remove the ABS MOTOR1 relay and ABS MOTOR2 relay.





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

Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY TO ENGINE ROOM NO.3 R/B)

(a) Disconnect the brake actuator assembly connector.





(b) Remove the ABS MOTOR1 relay and ABS MOTOR2 relay.

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

Resistance:





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

Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO ENGINE ROOM NO.3 R/B)

(a) Disconnect the skid control ECU (A13, A15) connectors.





(b) Remove the ABS MOTOR1 relay and ABS MOTOR2 relay.

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

Resistance:





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

Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

10. RECONFIRM DTC

(a) Clear the DTC Electronically Controlled Brake System.

(b) Turn the engine switch on (IG).

(c) Check if the same DTCs are recorded Electronically Controlled Brake System.

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

Result:





B -- REPLACE SKID CONTROL ECU

A -- END