Lexus SC300 / Lexus SC400. Service manual - part 633

INSPECTION OF IGNITION COIL

1. (RH 

IGNITION 

COIL)

REMOVE IGNITION COIL (See page 

IG–21

)

2. 

(LH IGNITION COIL)
DISCONNECT IGNITION COIL CONNECTOR AND HIGH–
TENSION CORD FROM IGNITION COIL

3. 

INSPECT PRIMARY COIL RESISTANCE
Using an ohmmeter, measure the resistance between posi-
tive (+) and negative (–) terminals.

Primary coil resistance (Cold): 0.40–0.50 

If the resistance is not as specified, replace the ignition coil.

4. 

INSPECT SECONDARY COIL RESISTANCE
Using an ohmmeter, measure the resistance between posi-
tive (+) and high–tension terminals.

Secondary coil resistance (Cold): 10.0–14.0 k

If the resistance is not as specified, replace the ignition coil.

5. 

(RH IGNITION COIL)
REINSTALL IGNITION COIL (See page 

IG–22

)

6. 

(LH IGNITION COIL)
RECONNECT IGNITION COIL CONNECTOR AND HIGH–
TENSION CORD FROM IGNITION COIL

–

 IGNITION SYSTEM

On–Vehicle Inspection

IG–9

INSPECTION OF CAM POSITION
SENSORS

1. 

DISCONNECT CAM POSITION SENSOR CONNECTORS
(a)  (RH Cam Position Sensor)

Disconnect the cam position sensor connector from the
ignition coil bracket.
(See steps 5 (a) on page 

IG–24

)

(b)  Disconnect the cam position sensor connectors.

2. 

INSPECT CAM POSITION SENSOR RESISTANCE
Using an ohmmeter, measure the resistance between termi-
nals.

Resistance (Cold):

835–1,350 

 at –10– +40

°

C (14–104

°

F)

If the resistance is not as specified, replace the cam position
sensor.

3. 

RECONNECT CAM POSITION SENSOR CONNECTORS

INSPECTION OF ENGINE SPEED
SENSOR

1. 

REMOVE ENGINE SPEED SENSOR
(See page 

IG–30

)

2. 

INSPECT ENGINE SPEED SENSOR RESISTANCE
Using an ohmmeter, measure the resistance between termi-
nals.

Resistance (Cold):

835–1,350 

 at –10– +40

°

C (14–104

°

F)

If the resistance is not as specified, replace the engine speed
sensor.

3. 

REINSTALL ENGINE SPEED SENSOR
(See page 

IG–30

)

INSPECTION OF ENGINE SPEED
SENSOR

(See procedure Spark Test on page 

IG–6

)

IG–10

–

 IGNITION SYSTEM

On–Vehicle Inspection

HIGH–TENSION CORDS AND CORD
CLAMPS

COMPONENTS FOR REMOVAL AND
INSTALLATION

REMOVAL OF HIGH–TENSION CORDS

1. 

DISCONNECT CABLE FROM NEGATIVE TERMINAL OF
BATTERY
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ”LOCK” position and the negative (–) termi-
nal cable is disconnected from the battery.

–

 IGNITION SYSTEM

High–Tension Cords and Cord Clamps

IG–11

2. 

REMOVE INTAKE AIR CONNECTOR
(a)  Disconnect the following hoses:

(1)  Air hose from ISC valve
(2)  Air hose (from PS air control valve) from intake air

connector

(b)  Remove the bolt holding the intake air connector to the

cylinder head cover.

(c)  Loosen the two hose clamps.
(d)  Disconnect the intake air connector from the throttle

body and air cleaner hose, and remove the throttle body.

3. 

REMOVE UPPER HIGH–TENSION CORD COVER
(a)  Remove the two mounting bolts.
(b)  Disconnect the front side claw groove of the cord cover

from the claw of the lower cover, and remove the cord
cover.

4. 

REMOVE RH ENGINE WIRE COVER
Remove the bolt and engine wire cover.

5. 

REMOVE LH ENGINE WIRE COVER
Remove the two bolts and engine wire cover.

IG–12

–

 IGNITION SYSTEM

High–Tension Cords and Cord Clamps