DTC C1A4A: Skid Control Buzzer Circuit [08/2016 - ]: Procedure

1. Check for DTCs of the pre-collision system.

   Refer to DTC CHECK / CLEAR [08/2016 - ]

   Body Electrical > Pre-Collision 2 > Trouble Codes 

   HINT: 

   The dynamic radar cruise control system only stores DTC C1A4A when the vehicle speed reaches 36 km/h (22 mph), however the pre-collision system stores this DTC at any vehicle speed. If DTC C1A4A is stored by the pre-collision system, perform troubleshooting of the pre-collision system first.

   Result

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

Result:  2

B 

GO TO PRE-COLLISION SYSTEM:  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - ] 

Result:  1

A 

See step  2

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [08/2016 - ]

   Powertrain > Radar Cruise2 > 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.

   1. Turn the ignition switch to ON.
   2. Turn the dynamic radar cruise control system on using the cruise control main switch (ON/OFF button).
   3. Drive the vehicle at 36 km/h (22 mph) or more for 1 second or more.
3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [08/2016 - ]

   Powertrain > Radar Cruise2 > Trouble Codes 

   Result

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

Result:  1

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 08/2017]  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2017 - ] 

Result:  2

B 

See step  3

1. Turn the ignition switch to ON.
2. Check that the skid control buzzer is sounds.

   Result

   Result	Proceed to
   The skid control buzzer does not sound when the ignition switch is ON.	A
   The skid control buzzer sounds continuously when the ignition switch is ON.	B

Result:  2

B 

See step  7

Result:  1

A 

See step  4

1. Disconnect the 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	Switch Condition	Specified Condition
   E72-2 (IG1) - Body ground	Ignition switch ON	11 to 14 V
   E72-2 (IG1) - Body ground	Ignition switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result:  2

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result:  1

OK 

See step  5

1. Disconnect the E72 skid control buzzer connector.
2. Disconnect the E71 driving support ECU assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E72-1 (BZ) - E71-3 (BZ)	Always	Below 1 Ω
   E72-1 (BZ) or E71-3 (BZ) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result:  2

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result:  1

OK 

See step  6

1. Remove the skid control buzzer.

   Refer to REMOVAL [08/2016 - ]

2. Inspect the skid control buzzer.

   Refer to INSPECTION [08/2016 - ]

   Result

   Proceed to
   OK
   NG

Result:  1

OK 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  COMPONENTS [08/2016 - ] 

Result:  2

NG 

REPLACE SKID CONTROL BUZZER. Refer to  COMPONENTS [08/2016 - ] 

1. Disconnect the E72 skid control buzzer connector.
2. Disconnect the E71 driving support ECU assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E72-1 (BZ) - E71-3 (BZ)	Always	Below 1 Ω
   E72-1 (BZ) or E71-3 (BZ) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result:  1

OK 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  COMPONENTS [08/2016 - ] 

Result:  2

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR