Open in Main Relay 1 Circuit - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1311/11-C1314/14: Open in Main Relay 1 Circuit
C1314/14 - Short in Main Relay 2 Circuit

DESCRIPTION

The main relay is built into the skid control ECU and supplies power to the master cut solenoid and linear solenoid valve.

The main relay remains on for approximately 2 minutes after the ignition 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 skid control ECU, perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (MAIN RELAY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(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 main relay when operating it using the Techstream.

Result:





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

2. 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 -- Continue to next step.

3. RECONFIRM DTC

(a) Turn the ignition switch off.

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

(c) Turn the ignition switch to ON.

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

Result:





B -- REPLACE SKID CONTROL ECU Removal

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

4. INSPECT ABS MAIN FUSES

(a) Turn the ignition switch off.





(b) Remove the ABS MAIN NO. 1 and ABS MAIN NO. 2 fuses from the engine room No. 3 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 NO. 1 and ABS MAIN NO. 2 fuses.





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

(c) Disconnect the A44 and A45 skid control ECU connectors.

(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) Reconnect the skid control ECU connectors.





(b) 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 SKID CONTROL ECU Removal