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Last Modified: 11-27-2007 1.6 C
Service Category: Brake Section: Brake Control/Dynamic Control System
Model Year: 2008 Model: LX570 Doc ID: RM000001DXT00JX
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DESCRIPTION (2008 LX570)

DTC

C1380/64

Stop Light Control Relay Malfunction

DESCRIPTION

Upon receiving the CRAWL or hill-start assist control operating signal from the skid control ECU, the relay contact turns on and the stop light comes on.

DTC Code

DTC Detection Condition

Trouble Area

C1380/64
  • When the voltage at the IG1 terminal is between 10 V and 14 V, the stop light driving output (STPO) is on, and a signal has not been input to the STP terminal for 5 seconds or more.
  • When the voltage at the IG1 terminal is between 10 V and 14 V, the stop light driving output (STPO) is off, and the input signal at the STP terminal is different from the input signal at the STP2 terminal for 5 seconds or more.
  • BRK LP relay
  • BRK LP relay circuit
  • Master cylinder solenoid (Skid control ECU)

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

When replacing the master cylinder solenoid, perform zero point calibration BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: CALIBRATION (2008 LX570) .

PROCEDURE

1.

CHECK STOP LIGHT SWITCH OPERATION

(a) Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

OK:

Stop light switch function is normal.

HINT:

Check the stop light bulb as it may have burned out.

OK

2.

INSPECT SKID CONTROL ECU (STP TERMINAL)

(a) Disconnect the A24 skid control ECU connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A24-7 (STP) - Body ground

Stop light switch on

(Brake pedal depressed)

8 to 14 V

A24-7 (STP) - Body ground

Stop light switch off

(Brake pedal released)

Below 1.5 V
OK

3.

INSPECT SKID CONTROL ECU (STP2 TERMINAL)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A24-45 (STP2) - Body ground

Stop light switch on

(Brake pedal depressed)

8 to 14 V

A24-45 (STP2) - Body ground

Stop light switch off

(Brake pedal released)

Below 1.5 V
OK

4.

PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT RELAY)

(a) Reconnect the A24 skid control ECU connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG) and turn the Techstream on.

(d) Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.

ABS/VSC/TRAC

Item

Test Part

Control Range

Diagnostic Note

Stop Light Relay

BRK LP relay

Relay ON/OFF

Observe the rear combination light (Does not come on for 5 seconds or more).

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

OK:

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

OK

5.

RECONFIRM DTC

(a) Clear the DTC BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(b) Check if the same DTC is output BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

HINT:

Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result

Result

Proceed to

DTC is output.

A

DTC is not output.

B
A

6.

INSPECT BRK LP RELAY (POWER SOURCE TERMINAL)

(a) Remove the BRK LP relay.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

1 - Body ground

Engine switch on (IG)

8 to 14 V

5 - Body ground

Always

11 to 14 V
OK

7.

INSPECT BRK LP RELAY

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 - 4

Battery positive (+) voltage is applied to terminal 1 and battery negative (-) voltage is applied to terminal 2

10 kΩ or higher

Battery positive (+) voltage is not applied to terminal 1 and battery negative (-) voltage is not applied to terminal 2

Below 1 Ω

3 - 5

Battery positive (+) voltage is applied to terminal 1 and battery negative (-) voltage is applied to terminal 2

Below 1 Ω

Battery positive (+) voltage is not applied to terminal 1 and battery negative (-) voltage is not applied to terminal 2

10 kΩ or higher
OK

8.

INSPECT SKID CONTROL ECU (STPO TERMINAL)

(a) Install the BRK LP relay.

(b) Disconnect the A24 skid control ECU connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

S37-16 (STPO) - Body ground

Engine switch on (IG)

11 to 14 V
OK

9.

RECONFIRM DTC

(a) Clear the DTC BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(b) Check if the same DTC is output BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

HINT:

Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result

Result

Proceed to

DTC is output.

A

DTC is not output.

B
A