Toyota Sequoia (2005). Manual - part 439

DI3CI–19

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–1551

1745

CIRCUIT INSPECTION

DTC

P0500/21 Vehicle speed sensor circuit malfunction

DTC

P0503/23 Vehicle speed sensor circuit malfunction

CIRCUIT DESCRIPTION

See page 

DI–278

.

DTC No.

DTC Detection Condition

Trouble Area

P0500/21

This trouble code is output when the vehicle speed signal from

the vehicle speed sensor is cut for 0.14 sec. or more while the

cruise control is in operation.

Vehicle speed sensor

Vehicle speed sensor signal circuit

ECM

P0503/23

Momentary interruption and noise are detected when a rapid

change of vehicle speed occurs while the cruise control is in

operation.

Vehicle speed sensor

Vehicle speed sensor signal circuit

ECM

WIRING DIAGRAM

See page 

DI–278

.

INSPECTION PROCEDURE

See page 

DI–278

.

I24840

Battery

1

17

1E

AM2

1

2

W–R

I18 
Ignition SW

B–R

IG2

8

5

E4

ECM

ST1–

1

STOP

16

5

S14
Stop Light SW

7

G–Y

3

6

E4

STP

1C

B–O

3

F10 FL Block

ALT

IGN1

B

B

W

1F

1L

1

2D

2C

15

W–R

AM2

ST2

1C

2

1J

2

4A

2

B–O

W

4

2

G–Y

Instrument Panel J/B

Sub J/B No. 4

Engine Room J/B

Instrument Panel J/B

4

L–B

Sub J/B No. 4

4D

1

1

4A

4E

DI–1552

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

1746

DTC

P0571/52 Stop light switch circuit malfunction

CIRCUIT DESCRIPTION

When the brake pedal is depressed, the stop light switch assy sends a signal to the ECM. When the ECM
receives this signal, it cancels the cruise control.
Fail–safe function operates to enable normal driving even if there is a malfunction in the stop light signal
circuit.
The cancel condition occurs when positive battery voltage is applied to terminal STP.
When the brake is applied, battery positive voltage is normally applied to terminal STP of the ECM through
the STOP fuse and the stop light switch assy, and the ECM turns the cruise control off.

DTC No.

DTC Detection Condition

Trouble Area

P0571/52

Stop light switch does not turn off even once the vehicle is

driven

Stop light switch assy

Stop light switch assy circuit

ECM

WIRING DIAGRAM

DIAB6–05

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–1553

1747

INSPECTION PROCEDURE

HINT:
When using the hand–held tester, start the inspection from step 1 and when not using the hand–held tester,
start from step 2.

1

Read value on hand–held tester.

PREPARATION:
(a)

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch to the ON position, and turn the hand–held tester main switch on.

(c)

Select the item ”STP LIGHT SW2 M”, ”STP LIGHT SW2 S” and ”STP LIGHT SW1 S” in the DATA LIST,
and read its value displayed on the hand–held tester.

CHECK:
Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal
is released.
CCS (ECM):

Item

Measurement Item

/Display (Range)

Normal Condition

Diagnostic Note

STP LIGHT SW2 M

Stop light SW signal (Main CPU)

/ON or OFF

ON: Brake pedal depressed

OFF: Brake pedal released

–

STP LIGHT SW2 S

Stop light SW signal (Sub CPU)

/ON or OFF

ON: Brake pedal depressed

OFF: Brake pedal released

–

STP LIGHT SW1 S

Stop light SW signal (Sub CPU)

/ON or OFF

ON: Brake pedal depressed

OFF: Brake pedal released

–

OK:

When the brake pedal is operated, the normal conditions listed above are shown on the display.

RESULT:

NG

A

OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)

B

OK (When troubleshooting according to the DTC chart)

C

B

Proceed to next circuit inspection shown in
problem symptoms table (See page 

DI–1541

).

C

Replace ECM (See page 

IN–35

).

A

I21525

Pushed in

Free

Stop Light Switch:

DI–1554

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

1748

2

Check operation of stop light.

CHECK:
Check that stop lights come on when the brake pedal is depressed, and go off when the brake pedal is re-
leased.
OK:

The stop lights operate normally.

OK

Go to step 5.

NG

3

Inspect stop light switch assy.

PREPARATION:
Disconnect the stop light switch assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Switch condition

Tester connection

Specified condition

Switch pin free

1 – 4

Below 1 

Ω

Switch pin free

2 – 3

10 k

Ω 

or higher

Switch pin pushed in

1 – 4

10 k

Ω 

or higher

Switch pin pushed in

2 – 3

Below 1 

Ω

NG

Replace stop light switch assy.

OK