Vehicle Stability Control System

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1251/51: Open in Pump Motor Circuit

DTC C1251/51 - Open in Pump Motor Circuit

DTC C1252/52 - Brake Booster Pump Motor on Time Abnormally Long

DTC C1253/53 - Pump Motor Relay Malfunction

DESCRIPTION





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MTR RELAY)
(a) Using the Techstream Active Test, generate a control command and then check that the ABS motor relay operates.

ABS/VSC/TRAC





OK:
Operation sounds of ABS motor is heard.
NG -- INSPECT RELAY (Marking: ABS MOTOR, TRAC MOTOR)
OK -- Continue to next step.
2. READ VALUE USING TECHSTREAM (PRESSURE SWITCH (PH AND PL))
(a) Check the Data List for proper functioning of the hydraulic brake booster pressure switch (PH and PL).
(1) Depress the brake pedal more than 40 times with the ignition switch OFF. Then turn the ignition switch ON and check the pressure switch (PH and PL) condition.

ABS/VSC/TRAC





HINT: When pressure in the power supply system is released, the brake pedal becomes easier to depress.

OK:
"OFF" turns to "ON".
OK -- REPLACE SKID CONTROL ECU
NG -- Continue to next step.
3. CHECK BRAKE BOOSTER PUMP ASSEMBLY




(a) Disconnect the B1 and B2 actuator connectors.
(b) Connect the battery positive (+) leads to terminals 2 (BM1) and 3 (BM2) of the actuator (pump motor) connector and battery negative (-) leads to terminals 1 (EM1) and 6 (EM2).
OK:
Operation sound of pump motor can be heard.
NG -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
OK -- Continue to next step.
4. CHECK BRAKE BOOSTER PRESSURE SWITCH (PH)




(a) Disconnect the B1 connector from the brake actuator.
(b) With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.
HINT: When pressure in the power supply system is released, the brake pedal becomes easier to depress.
(c) Measure the resistance between terminals PH and PHG of the brake actuator connector.
Standard resistance:
0.9 to 1.1 kOhms
(d) Connect the B1 connector to the brake actuator.
(e) Disconnect the B1 connector after the ignition switch has been turned ON and the pump motor has stopped.
(f) Measure the resistance between terminals PH and PHG of the brake actuator.
Standard resistance:
0 Ohms
HINT: After the inspection, connect the connector and clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NG -- REPLACE BRAKE ACTUATOR
OK -- Continue to next step.
5. CHECK BRAKE BOOSTER PRESSURE SWITCH (PL)




(a) Disconnect the B2 connector from the brake actuator.
(b) With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.
HINT: When pressure in the power supply system is released, the brake pedal becomes easier to depress.
(c) Measure the resistance between terminals PL and PLG of the brake actuator connector.
Standard resistance:
5.1 to 6.3 kOhms
(d) Connect the B2 connector to the brake actuator.
(e) Disconnect the B2 connector after the ignition switch has been turned ON and the pump motor has stopped.
(f) Measure the resistance between terminals PL and PLG of the brake actuator.
Standard resistance:
1.0 Ohms
HINT: After the inspection, connect the connector and clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NG -- REPLACE BRAKE ACTUATOR
OK -- Continue to next step.
6. CHECK WIRE HARNESS (BRAKE ACTUATOR - SKID CONTROL ECU AND BODY GROUND)




(a) Disconnect the B1 and B2 actuator connectors.
(b) Disconnect the S5 and S8 ECU connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE SKID CONTROL ECU
7. INSPECT RELAY (Marking: ABS MOTOR, TRAC MOTOR)




(a) Remove the ABS MOTOR relay and TRAC MOTOR relay from the engine room No. 2 relay block.
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE RELAY
OK -- Continue to next step.
8. CHECK WIRE HARNESS (ABS MOTOR RELAY AND TRAC MOTOR RELAY - BATTERY)




(a) Remove the ABS MOTOR relay and TRAC MOTOR relay from the engine room No. 2 relay block.
(b) Measure the voltage of the connectors.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
9. CHECK WIRE HARNESS (SKID CONTROL ECU - ABS MOTOR RELAY AND TRAC MOTOR RELAY)




(a) Remove the ABS MOTOR relay and TRAC MOTOR relay from the engine room No. 2 relay block.
(b) Disconnect the S5 and S8 ECU connectors.
(c) Measure the resistance of the connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
10. CHECK WIRE HARNESS (BRAKE ACTUATOR - ABS MOTOR RELAY AND TRAC MOTOR RELAY)




(a) Disconnect the B1 and B2 actuator connectors.
(b) Remove the ABS MOTOR relay and TRAC MOTOR relay from the engine room No. 2 relay block.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
11. CHECK WIRE HARNESS (SKID CONTROL ECU - BRAKE ACTUATOR)




(a) Disconnect the S8 ECU connector.
(b) Disconnect the B2 actuator connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE SKID CONTROL ECU