DTC C1A4B: Stop Light Relay Circuit [08/2013 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
5. Check for DTCs.

   Result

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

6. Turn the power switch off.

B → See step   11 

A: Go to next step 

1. Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

   OK

   Condition	Illumination Condition
   Brake pedal depressed	ON
   Brake pedal released	OFF

NG → See step   12 

OK: Go to next step 

Refer to ON-VEHICLE INSPECTION [08/2013 - ]

NG → See step   13 

OK: Go to next step 

1. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A24-33 (STP) - Body ground	Stop light switch assembly ON (Brake pedal depressed)	11 to 14 V
   A24-33 (STP) - Body ground	Stop light switch assembly OFF (Brake pedal released)	Below 1.5 V

   TEXT IN ILLUSTRATION
   
   

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

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 1F engine room junction block assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   1F-16 (STPS) - Body ground	Stop light switch assembly ON (Brake pedal depressed)	11 to 14 V
   1F-16 (STPS) - Body ground	Stop light switch assembly OFF (Brake pedal released)	Below 2 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Engine Room Junction Block Assembly)

3. Reconnect the 1F engine room junction block assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.
5. Select the Active Test on the Techstream.
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Stop Light Relay	Engine room junction block assembly	Relay ON/OFF	Stop lights come on

6. Select the Data List on the Techstream.
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Stop Light Relay Output	Engine room junction block assembly output / ON or OFF	ON: Relay output on OFF: Relay output off	-

7. Check stop light relay operation and stop light assembly operation on the Data List while performing the Active Test.

   Result

   Result	Proceed to
   Data List content and stop light operation are abnormal or Data List content is normal but stop lights do not turn on or off.	A
   Data List content and stop light operation are normal.	B

8. Turn the power switch off.

B → See step   8 

A: Go to next step 

1. Remove the engine room junction block assembly from the engine room relay block and junction block assembly.
2. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1G-3 (ACC) - A24-3 (STPO)	Always	Below 1 Ω
   1G-3 (ACC) or A24-3 (STPO) - Body ground	Always	10 kΩ or higher

4. Reconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
5. Install the engine room junction block assembly to the engine room relay block and junction block assembly.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the engine room junction block assembly from the engine room relay block and junction block assembly.
2. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1F-11 (STOP) - A24-6 (STP2)	Always	Below 1 Ω

4. Reconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
5. Install the engine room junction block assembly to the engine room relay block and junction block assembly.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the A24 skid control ECU (brake booster with master cylinder assembly) connector.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A24-6 (STP2) - Body ground	Stop light switch ON (Brake pedal depressed)	11 to 14 V
   A24-6 (STP2) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

   TEXT IN ILLUSTRATION
   
   

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

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

NG → See step   14 

OK: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .
4. Perform the following to make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the malfunction cannot be detected.

   1. Drive the vehicle at a speed for which cruise control operation is possible.
   2. Turn the cruise control system on using the cruise control switch (ON-OFF button).
   3. Push the cruise control switch to -/SET to begin control of vehicle speed using the cruise control system.
5. Enter the following menus: Powertrain / Radar Cruise / Trouble Codes.
6. Check for DTCs.

   Result

   Result	Proceed to
   DTC is not output	A
   DTC C1A4B is output	B

7. Turn the power switch off.

B → See step   15 

A → END