Lexus ES300 (1997 year). Manual - part 352

D00107

C8

C8

C8

II2

ID4

ID4

ID1

Combination Meter

ECM

Ignition Switch

Battery

Starter

Security ECU

E7

E7

E7

L

2

R

B+

NSW

14

J29

B

B

B–W

R–B

R–B

J27

J28

J27

Y

O

R–B

IG3

16

13

J29

D

D

D

1

10

15

L–W

Y

J29

E

E

E

Y

Y

4

3

8

5

6

2

Park/Neutral
Position Switch

J24

1H

1V

10

5

5

6

3

11

10

2

J8

J7

C

B

*1

*1

2J

2B

2D

2K

IG2

IF

F9

F9

F4

F6

AL

T

4

2

W

1K

1K

1B

1J

AM1

GAUGE

R–L

R–B

R–B

1

J28

1

R–L

R–L

R–L

A

A

1

S

T

 Relay

1

2

1

1

G–B

FL

 MAIN

*1: TMC Production

→

GR, TMM Procuction

→

B–O

B

1

2

3

11

5

9

1

2

3

5

L

R

2

6

11

8

C

A

C

R–B

O

Y

F

F

J26

II2

II2

B–W

B–W

B–W

B

B

R–B

IG3

E10

Instrument
Panel J/B

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–185

337

1997 LEXUS ES300   (RM511U)

DTC

P1780

Park/Neutral Position Switch Malfunction

CIRCUIT DESCRIPTION

The park/neutral position switch detects the shift lever position and sends signals to the ECM.
The ECM receives signals (NSW, R, 2 and L) from the park/neutral position switch. When the signal is not
sent to the ECM from the park/neutral position switch, the ECM judges that the shift lever is in D position.

DTC No.

DTC Detection Condition

Trouble Area

P1780

When driving under conditions (a) and (b) for 30 seconds or

more, the park/neutral position switch is ON (N position).

(2 trip detection logic)

(a) Vehicle speed: 70 km/h (44 mph) or more

(b) Engine speed: 1,500 

∼

 2,500 rpm

Short in park/neutral position switch circuit

Park/neutral position switch

ECM

WIRING DIAGRAM

DI0CZ–01

BE3840

D00052

D00042

ON

NSW

L

2

R

Position

P,N

R

D

2

L

NSW–Body
ground

R–Body
ground

2–Body
ground

L–Body
ground

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

0 V

9 

∼

 14 V*

9 

∼

 14 V

9 

∼

 14 V

9 

∼

 14 V

9 

∼

 14 V

9 

∼

 14 V

9 

∼

 14 V*

DI–186

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

338

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

Read PNP, REVERSE, 2ND and LOW signals.

When using LEXUS hand–held tester.
PREPARATION:
(a)

Remove the DLC3 cover.

(b)

Connect a LEXUS hand–held tester to the DLC3.

(c)

Turn the ignition switch ON and LEXUS hand–held tester
main switch ON.

CHECK:
Shift lever into the P, R, N, 2 and L positions, and read the PNP,
REVERSE, 2ND and LOW signals on the LEXUS hand–held
tester.
OK:

Shift position

Signal

2

2ND OFF 

→

 ON

L

LOW OFF 

→

 ON

R

REVERSE OFF 

→

 ON

P,N

NSW OFF 

→

 ON

When not using LEXUS hand–held tester.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure voltage between terminals NSW, 2, L and R of ECM
and body ground when the shift lever is shifted to the following
positions.
OK:

HINT: The voltage will drop slightly due to lighting up of the back
up light.

OK

Proceed to next circuit inspection shown on
matrix chart (See page 

DI–164

).

NG

Q07657

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–187

339

1997 LEXUS ES300   (RM511U)

2

Check park/neutral position switch.

PREPARATION:
(a)

Jack up the vehicle.

(b)

Remove the park/neutral position switch.

CHECK:
Check continuity between each terminal shown below when the
shift lever is moved to each position.

Shift Position

Terminal No. to continuity

P

2 – 7

5 – 6

R

2 – 8

–

N

2 – 9

5 – 6

D

2 – 10

–

2

2 – 3

–

L

2 – 4

–

OK:

There is continuity.

NG

Replace the park/neutral position switch.

OK

3

Check harness and connector between battery and park/neutral position switch,
park/neutral position switch and ECM (See page 

IN–27

).

NG

Repair or replace the harness and connector.

OK

Check and replace the ECM.

Q00758

Cruise Control ECU

14

OD

Y–B

7

B+

OD1

ECM

C15

E7

D00053

ON

OD1

(+)

(–)

DI–188

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

340

1997 LEXUS ES300   (RM511U)

O/D Cancel Signal Circuit

CIRCUIT DESCRIPTION

While driving uphill with cruise control activated, in order to minimize gear shifting and provide smooth cruis-
ing overdrive may be prohibited temporarily under some condition.
The cruise control ECU sends O/D cut signals to the ECM as necessary and the ECM cancels overdrive
shifting until these signals are discontinued.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check voltage between terminal OD1 of ECM and body ground.

PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure voltage between terminal OD1 of ECM and body
ground.
OK:

Voltage: 10 

∼

 14 V

OK

Proceed to next circuit inspection shown on
matrix chart (See page 

DI–164

).

NG

DI0D0–01