2001 TOYOTA AVALON Service Repair Manual

DI-58
- DIAGNOSTICSENGINE
214 Author
: Date
:
2001 AVALON (RM808U)
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 ConditionTrouble Area
P0300Misfiring of random cylinders is detected during any particular
200 or 1,000 revolutions
Open or short in engine wire

Connector connection

Vacuum hose connection
P0301
P0302
P0303For 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

Mass air flow meter

Engine coolant tempsensorP0303
P0304
P0305
P0306For any particular 1,000 revolutions of engine, misfiring is de-
tected which causes a deterioration in emission (2 trip detec-
tion logic)

Engine coolant temp. sensor

Compression pressure

Valve clearance

Valve timing

ECM
DI07S-10

A11083
Fusible
Link Block
Battery FL
MainB-O
B-W
2
2
2
2
2
21
1
1
1
1
1L
R
Y
W
GE5
IG Switch
No.1
No.2
No.3
No.4
No.5
No.6
Injector
W-B
ED
5
6
21
311
2
3
4#10
#20
#30
#40
#50
#60
E01
E02ECM
112B
2G
AM2
41 B
F6F7
11J
67
IF1 1C
2CIG23
5
W-RE4
E4
E4
E4
E4
E4E5
W-B
B-W
B-W
B-W
B-W
B-W22
2
2C2F
7
7
W-R
4
1
B
Driver Side J/BEngine Room J/B
W-B
EB
G DDL J8
J/C
B-WB-W B-WB-W B-W
IG2 Relay
W-B
B-O2
- DIAGNOSTICSENGINE
DI-59
215 Author
: Date
:
2001 AVALON (RM808U)
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.
WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
(a) Connect the TOYOTA hand-held tester or OBD II scan tool.
(b) Record the DTC and the freeze frame data.
(c) Use the TOYOTA hand-held tester to set to the check mode (See page DI-3).
(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 TOYOTA 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 SpeedTime
Idling3 minutes 30 seconds or more
1,000 rpm3 minutes or more
2,000 rpm1 minute 30 seconds or more
3,000 rpm1 minute or more

DI-60
- DIAGNOSTICSENGINE
216 Author
: Date
:
2001 AVALON (RM808U)
(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.
INSPECTION PROCEDURE
HINT:

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

Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame
data records 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 ºrichº (-20
% or less) or ºleanº (+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.
1 Check wire harness, connector and vacuum hose in engine room.
CHECK:
(a) Check the connection conditions of wire harness and connector.
(b) Check the disconnection, piping and break of vacuum hose.
NG Repair or replace, then confirm that there is no
misfire (See the confirmation driving pattern).
OK

B02101B04941
A06102
1.1 mm
A02024
ON
#10
#20 #40
(+)
#50 #60#30
(-)
- DIAGNOSTICSENGINE
DI-61
217 Author
: Date
:
2001 AVALON (RM808U)
2 Check spark plug and spark of misfiring cylinder.
PREPARATION:
(a) Remove the ignition coil (See page IG-5).
(b) Remove the spark plug.
CHECK:
(a) Check spark plug type.
(b) Check the electrode for carbon deposits.
(c) Check electrode gap.
OK:
(a) Iridium-tipped spark plug
Recommended spark plug:
DENSO made: SK20R11
NGK made: IFR6A11
(b) No large carbon deposit present.
Not wet with gasoline or oil.
(c) Electrode gap: 1.1 mm (0.043 in.)
PREPARATION:
(a) Install the spark plug to the ignition coil, and connect the
ignition coil connector.
(b) Disconnect the injector connector.
(c) Ground the spark plug.
CHECK:
Check if spark occurs while engine is being cranked.
OK:
Spark jumps across electrode gap.
NG Replace or check ignition system (See page
IG-1).
OK
3 Check voltage of ECM terminal for injector of failed cylinder.
PREPARATION:
(a) Remove the glove compartment (See page SF-82).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between applicable terminal of the ECM
connector and body ground.
OK:
Voltage: 9 - 14 V

FI6588
FI6538
A00064
10 V
/Division10 V
/Division
GND GND
100 msec./Division (Idling)1 msec./Division (Idling)
Injection duration
(Magnification) Injector Signal Waveform
DI-62
- DIAGNOSTICSENGINE
218 Author
: Date
:
2001 AVALON (RM808U)
Reference: INSPECTION USING OSCILLOSCOPE
With the engine idling, check the waveform between terminals #10 - #60 and E01 of the ECM connector.
HINT:
The correct waveform is as shown.
OK Go to step 5.
NG
4 Check resistance of injector of misfiring cylinder (See page SF-19).
NG Replace injector.
OK
Check for open and short in harness and con-
nector between injector and ECM (See page
IN-30).
5 Check fuel pressure (See page SF-6).
NG Check and repair fuel pump, fuel pipe line and
filter (See page SF-1).

- DIAGNOSTICSENGINE
DI-63
219 Author
: Date
:
2001 AVALON (RM808U)
OK
6 Check injector injection (See page SF-23).
NG Replace injector.
OK
7 Check mass air flow meter (See page SF-31) and engine coolant temperature
sensor (See page SF-73).
NG Repair or replace.
OK
Check compression pressure (See page
EM-3), valve clearance (See page EM-4) and
valve timing (See page EM-21).

A03315
Knock Sensor 1
(on Right Bank)
Knock Sensor 2
(on Left Bank)EB1 1
1W
W1
2W
WE4ECM
27
28KNKR
KNKLE1
E1 E4 EB1 DI-64
- DIAGNOSTICSENGINE
220 Author
: Date
:
2001 AVALON (RM808U)
DTC P0325 Knock Sensor 1 Circuit Malfunction (Bank 1)
DTC P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
CIRCUIT DESCRIPTION
Each of knock sensor is fitted to the right bank and left bank of the cylinder block to detect engine knocking.
This sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which
occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition timing is retarded
to suppress it.
DTC No.DTC Detecting ConditionTrouble Area
P0325No knock sensor 1 signal to ECM with engine speed between
2,000 rpm and 5,600 rpm
Open or short in knock sensor 1 circuit

Knock sensor 1 (looseness)

ECM
P0330No knock sensor 1 signal to ECM with engine speed between
2,000 rpm and 5,600 rpm
Open or short in knock sensor 2 circuit

Knock sensor 2 (looseness)

ECM
If the ECM detects the above diagnosis conditions, it operates the fail-safe function in which the corrective
retard angle value is set to the maximum value.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

DTC P0325 is for the right bank knock sensor circuit.

DTC P0330 is for the left bank knock sensor circuit.
DI07T-09