Lexus SC300 / Lexus SC400. Manual - part 739

OK

NG

NG

OK

INSPECTION PROCEDURE

1

Check shift position indicator.

Check that “P” lights up on the shift indicator when P position is shifted into, and that “P” is extin-
guished when shifting into another position.

P

Check and repair shift position indicator circuit (See
page 

BE–168

).

2

Check voltage between terminal P of ECU connector and body ground.

C

OK

P

Remove ECU with connectors still connected.

1.

Turn ignition switch on.

2.

Measure voltage between terminal P of ECU con-
nector and body ground when the shift lever is oper-
ated.

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

SR–52

).

Check for open in harness and connectors be-
tween ECU and [IK1] connector.

–

STEERING

STEERING COLUMN

SR–95

WIRING DIAGRAM

CIRCUIT INSPECTION

Parking Brake Switch Circuit

CIRCUIT DESCRIPTION

When the parking brake is operating, the parking brake switch sends a signal to the ECU. When this signal
is input to the ECU during tilt & telescopic, the ECU cancels tilt & telescopic.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

SR–96

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STEERING

STEERING COLUMN

OK

NG

NG

OK

NG

OK

OK

NG

INSPECTION PROCEDURE

1

Check operation of brake warning light.

Check that the brake warning light in the instrument panel comes on when the parking brake is opera-
tion with the engine running, and the light goes off when the parking brake is not operating.

C

Check brake warning light circuit.

2

Input signal check.

C

OK

1.

See input signal check.

2.

Check the indicator light when the parking brake is
operating.

The indicator light goes off when the parking brake
is operating.

Proceed to next circuit inspection shown on matrix
chart.

3

Check voltage between terminal PKB of tilt & telescopic ECU connector and body ground.

C

OK

P

Remove tilt & telescopic ECU with connectors still con-
nected.

1.

Turn ignition switch ON.

2.

Measure voltage between terminal PKB of tilt &
telescopic ECU connector and body ground, when
the parking brake lever is operating.

Proceed to next circuit inspection shown on matrix
chart.

4

Check for open in harness and connector between tilt & telescopic ECU and brake warning light
(See page  

IN–33

).

.

Repair or replace harness or connector

Check and replace tilt & telescopic ECU.

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STEERING

STEERING COLUMN

SR–97

SR–52

).

WIRING DIAGRAM

Door Courtesy Switch Circuit

CIRCUIT DESCRIPTION

The ECU determines the position of the driver’s door by monitoring the voltage at terminal DSW.

ÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑ

Door Position

ÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑ

Switch Position

ÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑ

DSW Voltage

ÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑ

Opened

ÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑ

Closed

ÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑ

Below 1 V

ÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑ

Closed

ÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑ

Opened

ÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑ

10–14 V

DIAGNOSTIC CHART

DIAGNOSTIC CHART

SR–98

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STEERING

STEERING COLUMN