ELECTRONICALLY CONTROLLED BRAKE SYSTEM Skid Control Buzzer Circuit

DESCRIPTION

A buzzer sounds to alert the driver when the vehicle-to-vehicle distance becomes less than the set value (for vehicles with a dynamic radar cruise control, pre-crash safety control or lane departure alert control).

WIRING DIAGRAM

*a	from IG1 NO. 4 Relay
*b	ECU-IG1 NO. 3
*c	Skid Control Buzzer Assembly
*d	Skid Control ECU (Brake Booster with Master Cylinder Assembly)

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK BUZZER OPERATION

   
   

   1. Confirm problem symptoms of the skid control buzzer assembly according to the customer problem analysis.

      Result
      Result Proceed to Buzzer does not sound. A Buzzer sounds constantly. B

   
   

   B

   INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

   A

2. PERFORM ACTIVE TEST USING GTS (SKID CONTROL BUZZER ASSEMBLY)

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the power switch on (IG).

   3. Select the Active Test on the GTS Click here.

      ABS/VSC/TRC

      Tester Display	Test Part	Control Range	Diagnostic Note
      DSS Signal Buzzer	Skid control buzzer assembly	Buzzer ON/OFF	Buzzer can be heard

   4. Check that the buzzer sounds/stops when turning the skid control buzzer assembly on/off using the GTS.

      Result
      Result Proceed to Buzzer does not sound. A Buzzer sounds/stops. B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.

   
   

   B

   USE SIMULATION METHOD TO CHECK Click here

   A

3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

   
   
   1. 

      Text in Illustration

      *a	Front view of wire harness connector (to Skid Control Buzzer Assembly)

      Turn the power switch off.

   2. Disconnect the H65 skid control buzzer assembly connector.

   3. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition H65-2 (IG1) - Body ground Power switch on (IG) 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

   OK

4. INSPECT SKID CONTROL BUZZER ASSEMBLY

   
   
   1. 

      Text in Illustration

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

      Turn the power switch off.

   2. Connect a negative (-) lead from the auxiliary battery to terminal 1 (BZ), and a positive (+) lead to terminal 2 (IG1) of the skid control buzzer assembly, and then check that the buzzer sounds.

      OK
      The skid control buzzer assembly sounds.

   
   

   NG

   REPLACE SKID CONTROL BUZZER ASSEMBLY Click here

   OK

5. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - SKID CONTROL BUZZER ASSEMBLY)

   
   

   1. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector 2 minutes after the power switch is turned off.

      Tech Tips

      Do not open/close the driver door within 2 minutes after the power switch is turned off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A24-13 (BZ) - H65-1 (BZ) Always Below 1 Ω A24-13 (BZ) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK HARNESS AND CONNECTOR (GND TERMINAL)

   
   
   1. 

      Text in Illustration

      *a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

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

      Standard Resistance
      Tester Connection Condition Specified Condition A24-28 (GND) - Body ground Always Below 1 Ω A24-27 (GND2) - Body ground Always Below 1 Ω A24-26 (GND3) - Body ground Always Below 1 Ω A24-25 (GND4) - Body ground Always Below 1 Ω A24-24 (GND5) - Body ground Always Below 1 Ω A24-23 (GND6) - Body ground Always Below 1 Ω

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

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.

   
   

   A

   REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

   B

   REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

   C

   REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

7. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

   
   

   1. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.

   2. Check the skid control buzzer assembly operation.

      Result
      Result Proceed to Buzzer stops (for LHD). A Buzzer stops (for RHD). B Buzzer sounds constantly. C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.

   
   

   A

   REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

   B

   REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

   C

8. REPLACE SKID CONTROL BUZZER ASSEMBLY

   
   

   1. Reconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.

   2. Replace the skid control buzzer assembly Click here.

   3. Check the skid control buzzer assembly operation.

      Result
      Result Proceed to Buzzer stops. A Buzzer sounds constantly. B

   
   

   A

   END

   B

9. CHECK IF CONNECTOR IS SECURELY CONNECTED

   
   

   1. Gently jiggle the connectors and wire harnesses and check the skid control buzzer assembly operation.

      Result
      Result Proceed to Buzzer stops. A Buzzer sounds constantly. B

   
   

   A

   END

   B

   REPAIR OR REPLACE HARNESS OR CONNECTOR