DTC C1A4A: Skid Control Buzzer Circuit [09/2014 - 11/2017]: Procedure

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [09/2014 - 11/2017]

   Powertrain > Radar Cruise > Clear DTCs 

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

   HINT: 

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

3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [09/2014 - 11/2017]

   Powertrain > Radar Cruise > 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

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - 08/2016]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 11/2017] 

Result: 

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 [09/2014 - 11/2017]  

Result: 

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 [09/2014 - 11/2017]  

Result: 

B 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the engine 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
   Radar Cruise Approach Alarm Buzzer	Skid control buzzer	ON or OFF	Buzzer can be heard

   Body Electrical > Pre-Collision 2 > Active Test 

   Tester Display
   Radar Cruise Approach Alarm Buzzer

   OK

   Skid control buzzer 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

Result: 

OK 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [09/2014 - 01/2023] 

Result: 

NG 

See step  3

1. Remove the skid control buzzer.

   Refer to REMOVAL [09/2014 - ]

2. Inspect the skid control buzzer.

   Refer to INSPECTION [09/2014 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE SKID CONTROL BUZZER. Refer to  REMOVAL [09/2014 - ] 

Result: 

OK 

See step  4

1. Disconnect the O40 skid control buzzer connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   O40-2 (IG1) - Body ground	Engine switch on (IG)	11 to 14 V
   O40-2 (IG1) - Body ground	Engine switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

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

Result: 

OK 

See step  5

1. Disconnect the O40 skid control buzzer connector.
2. Disconnect the B7 millimeter wave radar sensor assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   O40-1 (BZ) - B7-10 (BZ)	Always	Below 1 Ω
   O40-1 (BZ) or B7-10 (BZ) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

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

   Refer to REMOVAL [09/2014 - 11/2017]

2. Perform millimeter wave radar sensor assembly adjustment.

   Refer to ADJUSTMENT [09/2014 - 11/2017]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  7

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [09/2014 - 11/2017]

   Powertrain > Radar Cruise > Clear DTCs 

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

   HINT: 

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

3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [09/2014 - 11/2017]

   Powertrain > Radar Cruise > Trouble Codes 

   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

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

Result: 

A 

END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE) 

Result: 

B 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [09/2014 - 01/2023]