Lexus RX300 (MCU15). Manual — part 459

IG09P–02

B04941

–

IGNITION

IGNITION SYSTEM

IG–1

LEXUS RX300 (RM785E)

IGNITION SYSTEM

ON–VEHICLE INSPECTION

NOTICE:
”Cold” and ”Hot” in these sentences express the tempera-
ture of the coils themselves. ”Cold” is from –10

°C (14°F) to

50

°C (122°F) and ”Hot” is from 50°C (122°F) to 100°C

(212

°F).

1.

INSPECT IGNITION COIL WITH IGNITER AND
SPARK TEST

Check that the spark occurs.

(1)

Remove the ignition coil with igniters (See page
IG–6).

(2)

Using a 16 mm plug wrench, remove the spark
plugs.

(3)

Install the spark plugs to each ignition coil with ignit-
er, and connect the ignition coil with igniter connec-
tor.

(4)

Disconnect the injector connector.

(5)

Ground the spark plug.

(6)

Check if spark occurs while engine is being
cranked.

CHECK POWER SUPPLY TO IGNITION COIL WITH

SENSOR

SPARK TEST

Replace the crankshaft position sensor.

CHECK RESISTANCE OF CAMSHAFT POSITION

1. Turn ignition switch to ON.
2. Check that there is battery voltage at ignition coil positive (+)

terminal.

CHECK CONNECTION OF IGNITION COIL WITH

Resistance:

Cold

Hot

1,060 – 1,645 Ω

CHECK RESISTANCE OF CRANKSHAFT POSITION

(See page IG–13)

Resistance:

Cold

Hot

1,630 – 2,740 Ω

2,065 – 3,225 Ω

CHECK IGT SIGNAL FROM ECU

(See page DI–96)

TRY ANOTHER IGNITION COIL WITH IGNITER

Replace the camshaft position sensor.

Connect securely.

Check wiring between ignition switch

to ignition coil with igniter.

Check wiring between ECU and ignition
coil with igniter, and then try another ECU.

NO

OK

OK

OK

OK

BAD

BAD

BAD

BAD

BAD

SENSOR

835 – 1,400 Ω

IGNITER

CHANGE IT TO NORMAL IGNITION COIL WITH
IGNITER AND PERFORM SPARK TEST AGAIN

OK

Replace the ignition coil with igniter.

NO

OK

IGNITER CONNECTOR

(See page IG–10)

IG–2

–

IGNITION

IGNITION SYSTEM

LEXUS RX300 (RM785E)

NOTICE:
To prevent gasoline from being injected from injectors dur-
ing this test, crank the engine for no more than 5 – 10 se-
conds at time. If the spark done not occur, do the test as fol-
lows:

(7)

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

Torque: 17.5 N·m (180 kgf·cm, 13 ft·lbf)
(8)

Reinstall the ignition coil with igniters (See page
IG–7).

2.

INSPECT SPARK PLUGS

NOTICE:

S

Never use a wire brush for cleaning.

S

Never attempt to adjust the electrode gap on used
spark plug.

S

Spark plug should be replaced every 100,000 km
(60,000 miles).

(a)

Remove the ignition coil with igniters (See page
IG–6).

IG0147

Megger

Ground

B01301

B04942

16 mm Plug Wrench

IG0316

B02101

1.1 mm

–

IGNITION

IGNITION SYSTEM

IG–3

LEXUS RX300 (RM785E)

(b)

Check the electrode.

S

Using a megger (insulation resistance meter), mea-
sure the insulation resistance.

Correct insulation resistance:
10 MΩ or more

If the resistance is less than specified, proceed to step (d).
HINT:
If a megger is not available, the following simple method of in-
spection provides fairly accurate results.

S

Simple Method:

S

Quickly race the engine to 4,000 rpm 5 times.

S

Remove the spark plug. (See step (c))

S

Visually check the spark plug.
If the electrode is dry ... Okay.
If the electrode is wet ... Proceed to step (d).

S

Reinstall the spark plug. (See step (g))

(c)

Using a 16 mm plug wrench, remove the spark plugs.

(d)

Check the spark plug for thread damage and insulator
damage.

If abnormal, replace the spark plug.

Recommended spark plug:

DENSO

SK20R11

NGK

IFR6A11

(e)

Check the spark plug electrode gap.
Maximum electrode gap for used spark plug:
1.2 mm (0.047 in.)

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

Correct electrode gap for new spark plug:
1.0 – 1.1mm (0.039 – 0.043 in.)

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

IG0152

A06078

Ohmmeter

B02550

Ohmmeter

IG–4

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IGNITION

IGNITION SYSTEM

LEXUS RX300 (RM785E)

(f)

Clean the 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/cm

2

, 85 psi)

Duration:
20 seconds or less

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

Using a 16 mm plug wrench, install the spark plugs.
Torque: 17.5 N·m (180 kgf·cm, 13 ft·lbf)

(h)

Reinstall the ignition coil with igniters (See page
IG–7).

3.

INSPECT CAMSHAFT POSITION SENSOR

(a)

Remove the V–bank cover.

(b)

Remove the battery clamp cover.

(c)

Remove the air cleaner inlet.

(d)

Disconnect the camshaft position sensor connector.

(e)

Using an ohmmeter, measure the resistance between ter-
minals.
Resistance:

Cold

835 – 1,400 Ω

Hot

1,060 – 1,645 Ω

If the resistance is not as specified, replace the camshaft posi-
tion sensor.
(f)

Reconnect the camshaft position sensor connector.

(g)

Reinstall the air cleaner inlet.

(h)

Reinstall the battery clamp cover.

(i)

Reinstall the V–bank cover.

4.

INSPECT CRANKSHAFT POSITION SENSOR

Using an ohmmeter, measure the resistance between termi-
nals.

Resistance:

Cold

1,630 – 2,740 Ω

Hot

2,065 – 3,225 Ω

If the resistance is not as specified, replace the crankshaft posi-
tion sensor.