Lexus ES300 (2002 year). Manual - part 363

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-71

224

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

P0300

RANDOM/MULTIPLE CYLINDER MISFIRE
DETECTED

DTC

P0301

CYLINDER 1 MISFIRE DETECTED

DTC

P0302

CYLINDER 2 MISFIRE DETECTED

DTC

P0303

CYLINDER 3 MISFIRE DETECTED

DTC

P0304

CYLINDER 4 MISFIRE DETECTED

DTC

P0305

CYLINDER 5 MISFIRE DETECTED

DTC

P0306

CYLINDER 6 MISFIRE DETECTED

CIRCUIT DESCRIPTION

Misfire: The ECM uses the crank position sensor and camshaft position sensor to monitor changes in the
crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred.
When the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated, the
MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.

DTC No.

DTC Detecting Condition

Trouble Area

P0300

Misfiring of random cylinders is detected during any particular
200 or 1,000 revolutions

Open or short in engine wire

Connector connection

Vacuum hose connection

Ignition system

P0301
P0302
P0303

For any particular 200 revolutions for engine, misfiring is de-
tected which can cause catalyst overheating (This causes MIL
to blink)

Ignition system

Injector

Fuel pressure

Intake air flow meter

E.F.I. engine coolant temperature sensor

C

i

P0303
P0304
P0305
P0306

For any particular 1,000 revolutions of engine, misfiring is de-
tected which causes a deterioration in emission (2 trip detec-
tion logic)

Compression pressure

Valve clearance

Valve timing

PCV hose connection

ECM

HINT:
When the 2 or more codes for a misfiring cylinder are recorded repeatedly but no Random Misfire

 

code is

recorded, it indicates that the misfires were detected and recorded at different times.

051M6-09

A59742

7

3

2

3

4

7

IGN

#10

#20

E10

AM2

B - G

W - R

E10

E10

E10

E10

E10

2

W - B

W - B

1

B - R

IF3

E02

E01

#30

#40

Injector

Battery

FL MAIN

8

10

1L

1C

2

1E

EE

1

1

1A

B - R

B - R

B - R

B - R

2

B - R

B - R

B - R

B - G

8 IF6

6

Engine Room J/B

6

1

W - R

Ignition 
Switch

L

R

Y

W

Engine Room R/B

ECM

1

#50

#60

E10

E10

R - L

G

2

2

2

2

2

1

1

1

1

1

5

5

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6

05-72

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

225

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

(a)

Connect the hand-held tester or OBD II scan tool.

(b)

Record the DTC and the freeze frame data.

(c)

Use the hand-held tester to set to the check mode (See page 

05-5

).

(d)

Drive the vehicle several times with the engine speed, load and its surrounding range shown with the
ENGINE SPD, CALC LOAD in the freeze frame data or the MISFIRE RPM, MISFIRE LOAD in the data
list.

If you have no hand-held tester, turn the ignition switch OFF after the symptom is simulated the first time.
Then repeat the simulation process again.
HINT:
In order to memorize DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in the
data list for the following period of time.

Engine speed

Time

Idling

3 minutes 30 seconds or more

1,000 rpm

3 minutes or more

2,000 rpm

1 minute 30 seconds or more

3,000 rpm

1 minute or more

(e)

Check whether there is misfire or not by monitoring DTC and the freeze frame data. After that, record
them.

(f)

Turn the ignition switch OFF and wait at least 5 seconds.

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-73

226

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

HINT:

If is case that DTC besides misfire is memorized simultaneously, first perform the troubleshooting for
them.

Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame data re-
cords the engine conditions when the malfunction is detected. When troubleshooting, it is useful for
determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel
ratio was lean or rich, etc. at the time of the malfunction.

When the vehicle is brought to the workshop and the misfire is not occurred, misfire can be confirmed
by reproducing the condition or freeze frame data. Also, after finishing the repair, confirm that there
is no misfire. (See the confirmation driving pattern)

When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data
is besides the range of 

±

20 %, there is a possibility that the air-fuel ratio is inclining either to ”rich” (-20

% or less) or ”lean” (+20 % or more).

When COOLANT TEMP in the freeze frame data is less than 80

°

C (176

°

F), there is a possibility or

misfire only during warming up.

In the case that misfire cannot be reproduced, the reason may be because of the driving with lack or
fuel, the use of improper fuel, a stain of ignition plug, and etc.

B02101

B04941

1.1 mm

A06102

05-74

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

227

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

1

CHECK WIRE HERNESS, CONNECTOR AND VACUUM HOSE IN ENGINE ROOM

(a)

Check the connection conditions of wire harness and connector.

(b)

Check the disconnection, piping and break of vacuum hose.

NG

REPAIR OR REPLACE, THEM CONFIRM THAT
THERE IS NO MISFIRE

OK

2

CHECK CONNECTION OF PCV HOSE

NG

REPAIR OR REPLACE PCV HOSE

OK

3

INSPECT SPARK PLUG

(a)

Check electrode gap.
OK: 1.1 mm (0.043 in.)

(b)

Install the spark plug to the ignition coil, and connect the
ignition coil connector.

(c)

Disconnect the injector connector.

(d)

Ground the spark plug.

(e)

Check if spark occurs while engine is being cranked.
OK: Spark jumps across electrode gap.

NG

REPLACE SPARK PLUG

OK