engine TOYOTA PRIUS 2001 Service Repair Manual

± DIAGNOSTICSENGINE
DI±65
2001 PRIUS (RM778U)
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
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. And
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
P0300Mi fi i f d li d i d t t d d i ti l

Open or short in engine wire

Connector connection

Vacuum hose connection

I
gnition systemP0300
P0301
P0302
P0303
P0304
Misfiring of random cylinders is detected during any particular
200 or 1,000 revolutions
For any particular 200 revolutions for the engine, misfiring is
detected which can cause catalyst overheating
(This causes MIL to blink)

Ignition system

Injector

Fuel pressure

Manifold absolute pressure sensor

En
gine coolant temp. sensorP0304(This causes MIL to blink)
Engine coolant tem. sensor

Compression pressure

Valve clearance

Valve timing

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.

There is a case where the cylinder other than memorized has an accidental fire (the cylinder which is
one ahead of fired cylinder), so. at the time of checking all the checking items and if there is no ab-
normality, check the cylinder which is different from the recorded cylinder as fired.
DI6V8±03

A14053
Battery F13 A
B 1K
1 AM2 Engine RoomJ/B
W±R
71 1A
1E5
6Instrument
Panel J/B65
B±R
IG2
B±GR±W
B±W B±W
B±W
B±WI5
Injector No. 1
1
2C1
21
2
1 2
J1
J/C
B±W
L±W
1 9
2G
2BE8
E8
E7
E7Engine ECU
#10
#20
#30
#40 Y
11 3
I15
Ignition SW W±B1J
12
F12 A
MAIN
I6
Injector No. 2
I7
Injector No. 3
I8
Injector No. 4
1J
1B
AM2
A3
2G2
2
2
J7
J/C
B±W
B±W
B±W
B±WB±W
W±R
IG2
Relay
2 2
1 3
5
1 W±BFL Block No. 1
F18 FL Block No. 2 DI±66
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
(a) Connect the TOYOTA hand±held tester or OBD II scan tool.
(b) Record DTC and the freeze frame data.
(c) Use the TOYOTA hand±held tester to set to Check Mode. (See page DI±3)
(d) Drive the vehicle several times with the engine speed, load and its surrounding range shown with EN-
GINE SPD, CALC LOAD in the freeze frame data or 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
1000 rpm3 minutes or more
2000 rpm1 minute 30 seconds or more
3000 rpm1 minute or more
(e) Check whether there is misfire or not by monitoring DTC and the freeze frame data. After that, record
them.

P03792
± DIAGNOSTICSENGINE
DI±67
2001 PRIUS (RM778U)
(f) Turn ignition switch OFF and wait at least 5 seconds.
INSPECTION PROCEDURE
HINT:

If is the 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 warmed up or not, the air±fuel
ratio 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
2 Check spark plug and spark of misfiring cylinder.
PREPARATION:
Remove the spark plug (See page IG±1).
CHECK:
(a) Check for carbon deposits on electrode.
(b) Check electrode gap.
OK:
(a) No large carbon deposit present.
Not wet with gasoline or oil.
(b) Electrode gap: 1.0 ± 1.2 mm (0.039 ± 0.047 in.)
PREPARATION:
(a) Install the spark plug to ignition coil and connect the igni-
tion coil connector to ignition coil.

A13627
ON
#10
(+) (±) #20 #30 #40
FI6588
FI6538
A00064
Injector Signal Waveform
10V/
Division
GND
100 m sec./Division (Idling)GND
Injection duration1 m sec./Division (Idling) 10V/
Division(Magnification)
DI±68
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
(b) Disconnect the injector connector.
(c) Ground spark plug.
CHECK:
Check if spark occurs while engine is being cracked.
NOTICE:
To prevent excess fuel being injected from the injectors
during this test, don't crank the engine for more than 5 ± 10
seconds at a time.
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 ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between applicable terminal of the ECM con-
nector and body ground.
OK:
Voltage: 9 ± 14 V
Reference: INSPECTION USING OSCILLOSCOPE
INJECTOR SIGNAL WAVEFORM
With the engine idling, measure between terminals #10 ~ #40 and E01 of the ECM connector.
HINT:
The correct waveforms are shown.

± DIAGNOSTICSENGINE
DI±69
2001 PRIUS (RM778U)
OK Go to step 5.
NG
4 Check resistance of injector of misfiring cylinder (See page SF±9).
NG Replace injector.
OK
Check for open and short in harness and
connector between injector and ECM
(See page IN±41).
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump and fuel pipe line
(See page SF±1).
OK
6 Check injector injection (See page SF±12).
NG Replace injector.
OK
7 Check mass air flow merer and engine coolant temp. sensor
(See page SF±22 and SF±49).
NG Repair or replace.

DI±70
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
OK
Check compression pressure, valve
clearance and valve timing
(See page EM±3, EM±5, EM±21).

A14027
Knock
SensorECM
KNK1 E7 1
EA1128
B
BR
EB
BR(Shielded)
A
J8 A
J9J/C
± DIAGNOSTICSENGINE
DI±71
2001 PRIUS (RM778U)
DTC P0325 Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
The knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelec-
tric 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, 2,000
rpm or more
Open or short in knock sensor 1 circuit

Knock sensor 1 (looseness)

ECM
HINT:
If the ECM detects above diagnosis conditions, it operates the fail safe function in which the corrective retard
angle value is set to the maximum value.
WIRING DIAGRAM
DI6V9±02

A13628
E7 Connector LOCK
KNK1
DI±72
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame 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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Check continuity between terminal KNK1 of ECM connector and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Disconnect the E7 connector of the ECM.
CHECK:
Measure resistance between terminal KNK1 of the ECM con-
nector and body ground.
OK:
Resistance: 1 MW or higher
OK Go to step 3.
NG
2 Check knock sensor (See page SF±56).
NG Replace knock sensor.
OK
3 Check for open and short in harness and connector between ECM and knock
sensor (See page IN±41).
NG Repair or replace harness or connector.
OK

A00406
KNK signal waveform
0.5V/
Division
0V
0V5 m sec./Division
100
sec./Division 0.5V/
Division
± DIAGNOSTICSENGINE
DI±73
2001 PRIUS (RM778U)
4 Does malfunction disappear when a good knock sensor is installed?
YES Replace knock sensor.
NO
Check and replace ECM (See page IN±41).
Reference: INSPECTION USING OSCILLOSCOPE

With the engine racing (4,000 rpm) measure between ter-
minal KNK of the ECM connector and body ground.
HINT:
The correct waveforms are as shown.

Spread the time on the horizontal axis, and confirm that
period of the wave is 132 m sec.
(Normal mode vibration frequency of knock sensor:
8.1 kHz)
HINT:
If normal mode vibration frequency is not 8.1 kHz the sensor is
malfunctioning.

A14028
1
2R
E7
J/C
J8NE+ NE± C1
Camshaft
Position
Sensor
2
1 C6
Crankshaft
Position
Sensor
E8 E8
BRG
EBECM
BRBRG2
J8
J9 R G
A A
A24
16 10 (Shielded)
(Shielded)
BRG
DI±74
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P0335 Crankshaft Position Sensor ºAº Circuit
Malfunction
CIRCUIT DESCRIPTION
Crankshaft position sensor (NE signal) consist of a signal plate and pick up coil.
The NE signal plate has 34 teeth and is mounted on the crankshaft. The NE signal sensor generates 34
signals of every engine revolution. The ECM detects the standard crankshaft angle based on the G2 signals,
and the actual crankshaft angle the engine speed by the NE signals.
DTC No.DTC Detecting ConditionTrouble Area
No crankshaft position sensor signal to ECM during cranking.
(2 trip detection logic)
Open or short in crankshaft position sensor circuit.

Crankshaft position sensor
P0335No crankshaft position sensor signal to ECM with engine
speed 600 rpm or more
(2 trip detection logic)

Crankshaft osition sensor

Signal plate (Timing belt guide)

Crankshaft timing pulley

ECM
WIRING DIAGRAM
DI6VA±02