ELECTRONICALLY CONTROLLED BRAKE SYSTEM Skid Control Buzzer Circuit

DESCRIPTION

The skid control buzzer sounds while the accumulator pressure is abnormally low or an abnormality causing low fluid pressure occurs.

If the skid control buzzer circuit accumulator pressure is abnormally low, or an abnormal fluid pressure drop is occurring, the skid control buzzer sounds.

WIRING DIAGRAM

*a	Skid Control Buzzer
*b	VBZ
*c	Skid Control ECU

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SKID CONTROL BUZZER)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the engine switch on (IG) and turn the intelligent tester main switch on.

   3. Select Active Test mode on the intelligent tester.

      Skid control ECU:

      Tester Display	Vehicle Condition / Test Details	Control Range	Diagnostic Note
      Buzzer	Turns skid control buzzer	ON / OFF	Buzzer can be heard

   4. Check that the buzzer sounds/stops when turning the skid control buzzer on/off by using the intelligent tester.

      Result

      Result	Proceed to
      Buzzer does not sound or sounds constantly	A
      Buzzer sounds/stops (for LHD)	B
      Buzzer sounds/stops (for RHD)	C

      Tech Tips

      If troubleshooting has been carried out according to the "PROBLEM SYMPTOMS TABLE", refer back to the table and proceed to the next step Click here.

   
   

   B

   REPLACE SKID CONTROL ECU (for LHD) Click here

   C

   REPLACE SKID CONTROL ECU (for RHD) Click here

   A

2. INSPECT SKID CONTROL BUZZER (POWER SOURCE TERMINAL)

   
   
   1. 

      *1	Front view of wire harness connector: (to Skid Control Buzzer)

      Disconnect the L2 buzzer connector.

   2. Turn the engine switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition L2-2 - Body ground Engine switch on (IG) 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

   OK

3. INSPECT SKID CONTROL BUZZER

   
   
   1. 

      *a	Component without harness connected: (Skid Control Buzzer)

      Disconnect the skid control buzzer connector.

   2. Apply battery negative voltage to terminal 1, and battery positive voltage to terminal 2 of the skid control buzzer, and then check that the buzzer sounds.

      OK
      Skid control buzzer sounds.

   
   

   NG

   REPLACE SKID CONTROL BUZZER Click here

   OK

4. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - SKID CONTROL BUZZER)

   
   
   1. 

      *1	Front view of wire harness connector: (to Skid Control ECU)
      *2	VBZ
      *3	Front view of wire harness connector: (to Skid Control Buzzer)

      Disconnect the A19 ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition A19-22 (BZ) - L2-1 Always Below 1 Ω A19-22 (BZ) - Body ground Always 10 kΩ or higher A19-41 (VBZ) - L2-2 Always Below 1 Ω A19-41 (VBZ) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BODY GROUND)

   
   
   1. 

      *1	Front view of wire harness connector: (to Skid Control ECU)

      Disconnect the A19 and A21 ECU connectors.

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

      Standard resistance
      Tester Connection Condition Specified Condition A19-1 (GND) - Body ground Always Below 1 Ω A21-1 (GND4) - Body ground Always Below 1 Ω

      Tech Tips

      If troubleshooting has been carried out according to the "PROBLEM SYMPTOMS TABLE", refer back to the table and proceed to the next step before replacing the part Click here.

      Result

      Result	Proceed to
      OK (for LHD)	A
      OK (for RHD)	B
      NG	C

   
   

   A

   REPLACE SKID CONTROL ECU (for LHD) Click here

   B

   REPLACE SKID CONTROL ECU (for RHD) Click here

   C

   REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)