Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: When replacing the skid control ECU, perform zero point calibration and store system information (See CALIBRATION ).

HINT:

When C1249/49 is output together with C1380/64, inspect and repair the trouble areas indicated by C1249/49 first (See DTC C1249/49 OPEN IN STOP LIGHT SWITCH CIRCUIT ).

CHECK STOP LIGHT OPERATION

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

BRAKE PEDAL REFERENCE

Condition	Illumination Condition
Brake pedal depressed	ON
Brake pedal released	OFF

NG: INSPECT STOP LIGHT CIRCUIT (See PROBLEM SYMPTOMS TABLE )

OK: Go to next step

READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

Connect the Techstream to the DLC3
Turn the engine switch on (IG)

Select the Data List mode on the Techstream (See DATA LIST / ACTIVE TEST )

ABS/VSC/TRAC

NORMAL CONDITION

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	-

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: Go to step 9

OK: Go to next step

INSPECT SKID CONTROL ECU (STP2 TERMINAL)

Turn the engine switch off
Make sure that there is no looseness at the locking part and the connecting part of the connector.
Disconnect the skid control ECU connector.

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

Standard Voltage

STANDARD VOLTAGE

Tester Connection	Switch Condition	Specified Condition
A35-20 (STP2) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
A35-20 (STP2) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

Fig 1: Identifying Skid Control ECU (STP2 Terminal)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

OK: Go to next step

PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT CONTROL (BRK-LP) RELAY)

Reconnect the skid control ECU connector.
Connect the Techstream to the DLC3
Turn the engine switch on (IG)

Select the Active Test mode on the Techstream (See DATA LIST / ACTIVE TEST )

ABS/VSC/TRAC

CONTROL RANGE REFERENCE

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

Check that the "ON" and "OFF" of the stop lights can be shown on the rear combination light by the Techstream.
OK: The stop lights turn on or off in accordance with the Techstream.

NG: Go to step 6

OK: Go to next step

RECONFIRM DTC

Turn the engine switch off
Clear the DTCs (See DTC CHECK / CLEAR )
Turn the engine switch on (IG)
Perform a road test

Check if the same DTC is recorded (See DTC CHECK / CLEAR )

Result

RESULT REFERENCE

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

B: REPLACE SKID CONTROL ECU (See REMOVAL )

A: CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (See DIAGNOSIS SYSTEM )

INSPECT STOP LIGHT CONTROL RELAY (BRK-LP)

Turn the engine switch off.
Remove the stop light control (BRK-LP) relay

Measure the resistance according to the value(s) in the table below

Standard Resistance

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

Fig 2: Identifying Stop Light Control Relay (BRK-LP)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

OK: Go to next step

INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL)

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

Standard Voltage

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

Fig 3: Identifying Engine Room No. 3 Relay Block (Power Source Terminal)

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

OK: Go to next step

INSPECT SKID CONTROL ECU (STPO TERMINAL)

Install the stop light control (BRK-LP) relay
Make sure that there is no looseness at the locking part and the connecting part of the connector
Disconnect the skid control ECU connector.
Turn the engine switch on (IG)

Measure the voltage according to the value(s) in the table below

Standard Voltage

STANDARD VOLTAGE

Tester Connection	Switch Condition	Specified Condition
A35-21 (STPO) - Body ground	Engine switch on (IG)	11 to 14 V

Fig 4: Identifying Skid Control ECU (STPO Terminal)

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

OK: REPLACE SKID CONTROL ECU (See REMOVAL )

INSPECT SKID CONTROL ECU (STP1 TERMINAL)

Turn the engine switch off.
Make sure that there is no looseness at the locking part and the connecting part of the connector
Disconnect the skid control ECU connector

Measure the voltage according to the value(s) in the table below

Standard Voltage

STANDARD VOLTAGE

Tester Connection	Switch Condition	Specified Condition
J77-10 (STP1) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
J77-10 (STP1) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

Fig 5: Identifying Skid Control ECU (STP1 Terminal)

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

OK: REPLACE SKID CONTROL ECU (See REMOVAL )