Last Modified: 4-30-2014 6.6 C Doc ID: RM000000W8800HX
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0724; Brake Switch "B" Circuit High; 2006 MY LX470 [05/2005 -        ]

DTC

P0724

Brake Switch "B" Circuit High

DESCRIPTION

The purpose of this circuit is to prevent the engine from stalling while driving in the lock-up condition when the brakes are suddenly applied.

When the brake pedal is depressed, this switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in progress.

DTC No.

DTC Detection Condition

Trouble Area

P0724

Stop light switch remains ON even when vehicle is driven in GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) pattern 5 times (2 trip detection logic)

  • Short in stop light switch signal circuit
  • Stop light switch
  • ECM

MONITOR DESCRIPTION

This DTC indicates that the stop light switch remains ON. When the stop light switch remains ON during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC. The vehicle must GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) 5 times for 2 driving cycles in order for the DTC to be output.

MONITOR STRATEGY

Related DTCs

P0724: Stop light switch/Range check/Rationality

Required sensors/Components

Stop light switch, Vehicle speed sensor

Frequency of operation

Continuous

Duration

GO and STOP 5 times

MIL operation

2 driving cycles

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

The stop light switch remains on during GO and STOP 5 times.

GO and STOP is defined as follows:

The monitor will run whenever this DTC is not present.

None

GO: (Vehicle speed is 30 km/h (18.63 mph) or more)

Once

STOP: (Vehicle speed is less than 3 km/h (1.86 mph))

Once

Starter

OFF

Battery voltage

8 V or more

Ignition switch

ON

TYPICAL MALFUNCTION THRESHOLDS

Brake switch

Stuck ON

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

READ VALUE USING DATA LIST (STP SIGNAL)

HINT:

Using the intelligent tester's DATA LIST allows switch, sensor, actuator and other item values to be read without removing any parts. Reading the DATA LIST early in troubleshooting is one way to save time.

NOTICE:

In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

  1. Warm up the engine.
  2. Turn the ignition switch OFF.
  3. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
  4. Turn the ignition switch ON.
  5. Turn the intelligent tester ON.
  6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST.
  7. Read the DATA LIST using the intelligent tester.

Item

Measurement Item/

Range (Display)

Normal Condition

Diagnostic Note

STOP LIGHT SW

Stop light switch status/

ON or OFF

  • Brake pedal is depressed: ON
  • Brake pedal is released: OFF

-

OK

GO TO STEP 3

NG

2.

INSPECT STOP LIGHT SWITCH

(a) Remove the stop light switch.

(b) Measure the resistance of the switch.

Standard resistance:

Tester Connection

Switch Condition

Specified Condition

1 - 2

Pin pushed

(pedal released)

10 kΩ or higher

1 - 2

Pin not pushed

(pedal depressed)

Below 1 Ω

3 - 4

Pin pushed

(pedal released)

10 kΩ or higher

3 - 4

Pin not pushed

(pedal depressed)

Below 1 Ω

NG

REPLACE STOP LIGHT SWITCH

OK

3.

CHECK WIRE HARNESS (ECM - BATTERY)

(a) Check wire harness 2006 MY LX470 [05/2005 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE ECM