DTC C1380/64: Stop Light Control Relay Malfunction: Procedure

1. Remove the STOP fuse from the main body ECU.
   Fig 1: STOP Fuse

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   STOP (10 A) fuse	Always	Below 1 Ω

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   *1	Main Body ECU
   *2	STOP Fuse

NG → REPLACE STOP FUSE 

OK: Go to next step 

1. Install the STOP fuse.
2. Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

   OK

   Condition	Illumination Condition
   Brake pedal depressed	ON
   Brake pedal released	OFF

NG → INSPECT STOP LIGHT CIRCUIT 

OK: Go to next step 

1. Disconnect the skid control ECU connector.
   Fig 2: A36 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   A36-27 (STP1) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
   A36-27 (STP1) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

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   *1	Skid Control ECU Harness Side Connector Front View

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STP1 CIRCUIT) 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 3: A36 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   Tester Connection	Condition	Specified Condition
   A36-27 (STP1) - A36-21 (STP2)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Skid Control ECU Harness Side Connector Front View

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT) 

OK: Go to next step 

1. Reconnect the skid control ECU connector.
2. Connect Techstream to the DLC3.
3. Start the engine.
4. Select the Active Test on Techstream.
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Stop Light Relay	Stop light control relay	Relay ON/OFF	Stop light comes on

5. Check that the "ON" and "OFF" of the stop light can be shown on the rear combination light by Techstream.

   OK

   The stop light turns on or off in accordance with Techstream.

OK → See step   9 

NG: Go to next step 

1. Turn the engine switch off.
   Fig 4: Identifying Stop Light Control (BRK) Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Remove the stop light control relay (BRK relay).
3. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   3 - 4	Always	Below 1 Ω
   3 - 5	Always	10 kΩ or higher
   3 - 4	When battery positive voltage is applied to terminal 1 and battery negative voltage to terminal 2	10 kΩ or higher
   3 - 5	When battery positive voltage is applied to terminal 1 and battery negative voltage to terminal 2	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Stop Light Control Relay (BRK Relay)

NG → REPLACE STOP LIGHT CONTROL RELAY (BRK RELAY) 

OK: Go to next step 

1. Measure the voltage according to the value(s) in the table below.
   Fig 5: Engine Room Relay Block (Power Source Terminal)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard voltage

   Tester Connection	Condition	Specified Condition
   Stop light control relay terminal 5 - Body ground	Always	8 to 14 V
   Stop light control relay terminal 2 - Body ground	Engine switch on (IG)	8 to 14 V

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   *1	Engine Room R/B
   *2	Stop Light Control Relay (BRK Relay)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

OK: Go to next step 

1. Turn the engine switch off.
   Fig 6: A36 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Install the stop light control relay (BRK relay).
3. Disconnect the skid control ECU connector.
4. Turn the engine switch on (IG).
5. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   A36-16 (STPO) - Body ground	Engine switch on (IG)	10 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Skid Control ECU Harness Side Connector Front View

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STPO CIRCUIT) 

OK: Go to next step 

1. Turn the engine switch off.
2. Reconnect the skid control ECU connector.
3. Clear the DTC. Refer to DTC CHECK/CLEAR .
4. Perform a road test.
5. Check if the same DTC is recorded. Refer to DTC CHECK/CLEAR .

   Result

   Condition	Proceed to
   DTC (C1380/64) is not output	A
   DTC (C1380/64) is output	B

B → REPLACE BRAKE ACTUATOR ASSEMBLY 

A → CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)