DTC C1A4A: Skid Control Buzzer Circuit [02/2014 - 11/2016]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [02/2014 - 11/2016]

4. Make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the system cannot detect the malfunction.

5. Enter the following menus: Body Electrical / Pre-Collision 2 / Trouble Codes.
6. Check for DTCs.

   Body Electrical > Pre-Collision 2 > Trouble Codes 

   Result

   Result	Proceed to
   DTC C1A4A and U0235 are not output	A
   DTC C1A4A and U1104 are not output
   DTC C1A4A is output	B
   DTC C1A4A and U0235 are output	C
   DTC C1A4A and U1104 are output	D

7. Turn the power switch off.

Result:  1

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [02/2014 - 11/2016] 

Result:  3

C 

GO TO DTC U0235. Refer to  DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1104: Lost Communication with Driving Support ECU [02/2014 - 11/2016]  

Result:  4

D 

GO TO DTC U1104. Refer to  DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1104: Lost Communication with Driving Support ECU [02/2014 - 11/2016]  

Result:  2

B 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Pre-Collision 2 / Active Test.
5. Perform "Active Test" according to the display on the Techstream.

   Body Electrical > Pre-Collision 2 > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   PCS Crash Alarm Buzzer	Skid control buzzer assembly	ON or OFF	Buzzer can be heard
   PCS Approach Alarm Buzzer	Skid control buzzer assembly	ON or OFF	Buzzer can be heard

   Body Electrical > Pre-Collision 2 > Active Test 

   Tester Display
   PCS Crash Alarm Buzzer

   Body Electrical > Pre-Collision 2 > Active Test 

   Tester Display
   PCS Approach Alarm Buzzer

   OK

   Skid control buzzer assembly sounds.

   NOTE:

   When replacing the driving support ECU assembly, always replace it with a new one. If a driving support ECU assembly which was installed to another vehicle is used, the information stored in the driving support ECU assembly will not match the information from the vehicle. As a result, a DTC may be stored.

   Result

   Proceed to
   OK
   NG

6. Turn the power switch off.

Result:  1

OK 

See step  6

Result:  2

NG 

See step  3

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK

   The skid control buzzer sounds.

3. Install the skid control buzzer assembly.

   Result

   Proceed to
   OK
   NG

Result:  2

NG 

REPLACE SKID CONTROL BUZZER ASSEMBLY 

Result:  1

OK 

See step  4

1. Disconnect the A59 skid control buzzer assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A59-2 (IG1) - Body ground	Power switch on (IG)	11 to 14 V
   A59-2 (IG1) - Body ground	Power switch off	Below 1 V

3. Reconnect the A59 skid control buzzer assembly connector.

   Result

   Proceed to
   OK
   NG

Result:  2

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - AUXILIARY BATTERY) 

Result:  1

OK 

See step  5

1. Disconnect the A59 skid control buzzer assembly connector.
2. Disconnect the A3 millimeter wave radar sensor assembly connector.
3. Disconnect the S4 lane departure warning camera connector (w/ Lane Departure Alert System).
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A59-1 (BZ) - A3-10 (BZ)	Always	Below 1 Ω
   A59-1 (BZ) or A3-10 (BZ) - Body ground	Always	10 kΩ or higher

5. Reconnect the S4 lane departure warning camera connector (w/ Lane Departure Alert System).
6. Reconnect the A3 millimeter wave radar sensor assembly connector.
7. Reconnect the A59 skid control buzzer assembly connector.

   Result

   Proceed to
   OK
   NG

Result:  2

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

Result:  1

OK 

See step  6

1. Replace the millimeter wave radar sensor assembly with a new one.

   Refer to REMOVAL [02/2014 - 11/2016]

NEXT 

1. Perform millimeter wave radar sensor assembly adjustment.

   Refer to ADJUSTMENT [02/2014 - 11/2016]

NEXT 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [02/2014 - 11/2016]

4. Make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the system cannot detect the malfunction.

5. Enter the following menus: Body Electrical / Pre-Collision 2 / Trouble Codes.
6. Check for DTCs.

   Body Electrical > Pre-Collision 2 > Trouble Codes 

   Result

   Result	Proceed to
   DTC C1A4A is not output	A
   DTC C1A4A is output	B

7. Turn the power switch off.

Result:  1

A 

END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE) 

Result:  2

B 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  COMPONENTS [02/2014 - ]