Lexus SC300 / Lexus SC400. Manual - part 524

4. 

VISUALLY INSPECT SPARK PLUGS
Check the spark plug for thread damage and insulator dam-
age.
If abnormal, replace the spark plug.

Recommended spark plug:   ND PK20R11

NGK BKR6EP11

5. 

INSPECT ELECTRODE GAP

Maximum electrode gap: 1.3 mm (0.051 in.)

If the gap is greater than maximum, replace the spark plug.

Correct electrode gap of new spark plug:

1.1 mm (0.043 in.)

NOTICE: If adjusting the gap of a new spark plug, bent
only the base of the ground electrode. Do not touch the
tip. Never attempt to adjust the gap on the used plug.

6. CLEAN 

SPARK 

PLUGS

If the electrode has traces of wet carbon, allow it to dry and
then clean with a spark plug cleaner.

Air pressure:   Below 588 kPa (6 kgf/cm2, 85 psi)

Duration: 

20 seconds or less

HINT: If there are traces of oil, remove it with gasoline before
using the spark plug cleaner.

7. REINSTALL 

SPARK 

PLUGS

Using a 16 mm plug wrench, install the spark plug.

Torque:   18 N

⋅

m (180 kgf

⋅

cm, 13 ft

⋅

lbf)

8.  RECONNECT HIGH–TENSION CORDS  TO SPARK

PLUGS
(See steps 4 to 13 on pages 

IG–16

 to 19)

IG–8

–

 IGNITION SYSTEM

On–Vehicle Inspection

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