Abnormal Brake Pedal Response on First Depression [03/2017 - ]: Procedure

1. Check the conditions at the time the problem occurred.
   1. Whether a warning light illuminated or the buzzer sounded.
   2. The number of times the engine switch was turned on (IG) since the latest symptom occurred.
   3. Frequency of the symptom.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [03/2017 - 09/2018] , or refer to DTC CHECK / CLEAR [09/2018 - ]

   Chassis > ABS/VSC/TRAC > Clear DTCs 

2. Turn the engine switch off.
3. Turn the engine switch on (IG).
4. Check the DTCs (electronically controlled brake system) that are output.

   Refer to DTC CHECK / CLEAR [03/2017 - 09/2018] , or refer to DTC CHECK / CLEAR [09/2018 - ]

   Chassis > ABS/VSC/TRAC > Trouble Codes 

   Result

   Result	Proceed to
   DTCs C1391 and C1256 are not output.	A
   DTCs C1391 and/or C1256 are output.	B

Result: 

B 

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2017 - 09/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2018 - 05/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [05/2023 - ] 

Result: 

A 

See step  3

1. Turn the engine switch off.
2. Depress the brake pedal within 2 minutes of opening the driver door and check the response of the brake pedal.
3. Release the brake pedal and wait for 2 minutes without depressing the brake pedal, opening or closing the driver door or operating the engine switch.
4. After 2 seconds or more have elapsed, depress the brake pedal and check that the first depression response is different to successive depression responses.

   HINT: 

   Compare the response of the brake pedal when the system is in sleep mode and when the stroke simulator is operating.

   Result

   Result	Proceed to
   The response of the brake pedal does not change.	A
   The response of the brake pedal changed.	B

Result: 

B 

END 

Result: 

A 

See step  4

1. Set the interior light door switch to ON and check that the map light assembly illuminates, then set the interior light door switch to DOOR.
2. Check that the map light assembly illuminates when the driver door is opened.

   OK

   The map light assembly illuminates when the driver door is opened.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

INSPECT LIGHTING SYSTEM (COURTESY LIGHT SWITCH CIRCUIT). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - ] 

Result: 

OK 

See step  5

1. Measure the voltage and waveform according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Skid Control ECU Assembly)

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A8-14 (CTY) - Body ground	Driver door open	Below 1 V
   A8-14 (CTY) - Body ground	Driver door closed	Pulse generation (waveform 1)

   1. Waveform 1 (Reference)

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      *a	Driver door closed
      *b	Driver door open

      Item	Content
      Tester Connection	A8-14 (CTY) - Body ground
      Tool Setting	5 V/DIV., 10 ms./DIV.
      Vehicle Condition	Driver door closed → open

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (CTY CIRCUIT)