DTC C1380: Stop Light Control Relay Malfunction: Procedure

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 

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Select the Data List on the Techstream. Refer to DATA LIST / ACTIVE TEST .
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Stop Light SW	Stop light switch / ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

4. Check that the stop light switch condition observed on the Techstream changes according to brake pedal operation.

   OK

   The Techstream displays ON or OFF according to brake pedal operation.

NG → See step   9 

OK: Go to next step 

1. Select the Active Test on the Techstream. Refer to DATA LIST / ACTIVE TEST .
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Stop Light Relay	Stop light control (BRK-LP) relay	Relay ON/OFF	Stop lights come on

2. Check that the stop lights turn on or off in accordance with the Techstream.

   OK

   The stop lights turn on or off in accordance with the Techstream.

NG → See step   6 

OK: Go to next step 

1. Turn the engine switch off.
   Fig 1: Identifying Skid Control ECU STP2 Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
3. Disconnect the skid control ECU connector.
4. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A62-22 (STP2) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
   A62-22 (STP2) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Skid Control ECU)

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

OK: Go to next step 

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

   Result

   Result	Proceed to
   DTC (C1380) is not output	A
   DTC (C1380) is output	B

B → See step   11 

A → See step   10 

1. Turn the engine switch off.
   Fig 2: Stop Light Control (BRK-LP) Relay

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 4	Voltage is not applied between terminals 1 and 2	Below 1 Ω
   3 - 5	Voltage is not applied between terminals 1 and 2	10 kΩ or higher
   3 - 4	Voltage is applied between terminals 1 and 2	10 kΩ or higher
   3 - 5	Voltage is applied between terminals 1 and 2	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Stop Light Control (BRK-LP) Relay

NG → REPLACE STOP LIGHT CONTROL (BRK-LP) RELAY 

OK: Go to next step 

1. Measure the voltage according to the value(s) in the table below.
   Fig 3: Identifying No. 2 Engine Room Relay Block Power Source Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Stop light control (BRK-LP) relay terminal 5 - Body ground	Always	11 to 14 V
   Stop light control (BRK-LP) relay terminal 2 - Body ground	Engine switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	No. 3 Engine Room Relay Block
   *2	Stop Light Control (BRK-LP) Relay

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

OK: Go to next step 

1. Install the stop light control (BRK-LP) relay.
   Fig 4: Identifying Skid Control ECU STPO Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
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	Switch Condition	Specified Condition
   A62-31 (STPO) - Body ground	Engine switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Skid Control ECU)

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

OK → See step   11 

1. Turn the engine switch off.
   Fig 5: Identifying Skid Control ECU STP1 Terminal Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
3. Disconnect the skid control ECU connector.
4. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A62-2 (STP1) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
   A62-2 (STP1) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Skid Control ECU)

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

OK → See step   11