Lexus ES300 (1997 year). Manual - part 320

–

DIAGNOSTICS

ENGINE

DI–57

209

1997 LEXUS ES300   (RM511U)

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 crankshaft 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 the any

particular 200 or 1,000 revolutions

Ignition system

Injector

P0301

P0302

P0303

For any particular 200 revolutions for the engine, misfiring is

detected which can cause catalyst overheating

(This causes MIL to blink)

j

Fuel line pressure

EGR

Compression pressure

Valve clearance not to specification

P0303

P0304

P0305

P0306

For any particular 1,000 revolutions of the engine, misfiring is

detected which causes a deterioration in emission

(2 trip detection logic)

Valve clearance not to specification

Valve timing

Mass air flow meter

Engine coolant temp. sensor

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.

DI09O–01

S05469

Instrument

Fusible
Link
Block

Engine

Battery

FL
MAIN

B–G

B–R

B–R

B–R

W–R

J22
Junction
Connector

B–R

B–R

B–R

B–R

B–R

B–R

2

2

2

2

2

2

1

1

1

1

1

1

L

R

Y

W

R–L

G

E10

E10

E10

E10

E10

E10

E10

E10

Ignition
Switch

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6

Injector

BR

BR

ED

IK3

10

9

34

33

8

7

6

5

#10

#20

#30

#40

#50

#60

E01

E02

ECM

12

2L

2A

AM2

4

1

B

F6

F8

1

1

6

7

1K

1K

1C

1B

3

8

5

5

Panel J/B

Room
J/B

FI6588 FI6538

A00064

10V

/Division

10V

/Division

GND

GND

100 m sec./Division (Idling)

1 m sec./Division (Idling)

Injection duration

(Magnification)

DI–58

–

DIAGNOSTICS

ENGINE

210

1997 LEXUS ES300   (RM511U)

WIRING DIAGRAM

Reference INSPECTION USING OSCILLOSCOPE
INJECTOR SIGNAL WAVEFORM
With the engine idling, measure between terminals #10 

∼

 #60 and E01 of ECM.

HINT:The correct waveform is as shown.

A00221

P25779
P23917

–

DIAGNOSTICS

ENGINE

DI–59

211

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

Check spark plug and spark of misfiring cylinder.

PREPARATION:
(a)

Remove the ignition coil (See page 

IG–7

).

(b)

Remove the spark plug.

CHECK:

(1)

Check spark plug type.

(2)

Check for carbon deposits on electrode.

(3)

Check electrode gap.

OK:

(1)  Twin ground electrodes type.
Recommended spark plug:
ND    PK20TR11
NGK  BKR6EKPB–11
(2)  No large carbon deposit present.
      Not wet with gasoline or oil.
(3)  Electrode gap:  1.1 

∼

 1.3 mm (0.043 

∼

 0.051 in.)

PREPARATION:
(a)

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

(b)

Disconnect injector connector.

(c)

Hold the end about 12.5 mm (0.5 in.) from the ground.

CHECK:
Check if spark occurs while engine is being cranked.
NOTICE:To prevent excess fuel being injected from the
injectors during this test, don’t crank the engine for more
than 5 

∼

 10 sec. at a time.

OK:

Spark jumps across electrode gap.

NG

 Replace or check ignition system 
(See page 

IG–1

).

OK

A00222

ON

(+)

#10

(+)

#20

(+)

#40

(+)

#50

(+)

#60

(+)

#30

BE6653
P24319

DI–60

–

DIAGNOSTICS

ENGINE

212

1997 LEXUS ES300   (RM511U)

2

Check voltage of ECM terminal for injector of failed cylinder.

PREPARATION:
(a)

Remove the glove compartment (See page 

SF–64

).

(b)

Turn ignition switch ON.

CHECK:
Measure voltage between applicable terminal of ECM connec-
tor and body ground.
OK:

Voltage:  9 

∼

 14 V

OK

 Go to step 4.

NG

3

Check resistance of injector of misfiring cylinder (See page 

SF–16

).

NG

 Replace injector.

OK

Check for open and short in harness and
connector between injector and ECM
(See page 

IN–27

).

4

Check fuel pressure (See page 

SF–6

).

NG

 Check and repair fuel pump, fuel pipe line and
  filter (See page 

SF–1

).

OK