C1312

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1311/11, C1312/12: Open in Main Relay 1 Circuit


DESCRIPTION

The ABS main relay supplies power to the changeover solenoid and the linear solenoid.

The ABS main relay remains on for approximately 2 minutes after the power switch is turned off and the input of brake pedal operation signals stops, and supplies power to the system to keep it ready to operate.





WIRING DIAGRAM

Refer to DTCs C1241/41 and C1242/42 C1241.

INSPECTION PROCEDURE

NOTICE:
When replacing the brake booster with master cylinder (skid control ECU), perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MAIN RELAY)

(a) Connect the Techstream to the DLC3.

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

(c) Select the Active Test on the Techstream Data List / Active Test.

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(d) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(e) Check the operating condition of the ABS main relay when operating it with the Techstream.

Result:





B -- INSPECT ABS MAIN FUSES
A -- Continue to next step.

2. INSPECT SKID CONTROL ECU (BS TERMINAL)

(a) Turn the power switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the skid control ECU connector.

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

Standard Voltage:





Text in Illustration





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

3. RECONFIRM DTC

(a) Reconnect the skid control ECU connector.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the power switch on (IG).

(d) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting

4. INSPECT ABS MAIN FUSES

(a) Turn the power switch off.





(b) Remove the ABS MAIN fuses from the engine room relay block.

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

Standard Resistance:





Text in Illustration





NG -- REPLACE ABS MAIN FUSES
OK -- Continue to next step.

5. INSPECT SKID CONTROL ECU (BI TERMINAL)

(a) Install the ABS MAIN fuses.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the skid control ECU connector.

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

Standard Voltage:





Text in Illustration





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

6. INSPECT SKID CONTROL ECU (BS TERMINAL)

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





Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BS CIRCUIT)

OK -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal