check engine TOYOTA PRIUS 2001 Service Manual PDF

A09300
Vehicle speed
40 km/h
(25 mph)
Idling(c)(d)
(e)
(a)
IG SW OFF
(b)
(e)
60 sec.
or more(d)
(d) Once
40 sec.
or moreTwice
40 sec.
or more11 times
40 sec.
or more
10 sec. 10 sec.(e)
10 sec.
± DIAGNOSTICSENGINE
DI±59
2001 PRIUS (RM778U)
DTC P0136 Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page DI±44.
DTC No.DTC Detecting ConditionTrouble Area
P0136
Voltage output of the heated oxygen sensor remains at 0.45 V
or more, or 0.55 V or less when the vehicle is driven at 40 km/h
(25 mph) or more after the engine is warmed up.
(2 trip detection logic).

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
HINT:
Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 on page DI±44.
CONFIRMATION DRIVING PATTERN
(a) Connect the hand±held tester to the DLC3.
(b) Switch the hand±held tester from the Normal Mode to the Check (Test) Mode (See page DI±3).
(c) Start the engine and let the engine idle for 60 seconds or more.
(d) Drive the vehicle at 40 km/h (25 mph) or more for 40 seconds or more.
(e) Let the engine idle for 10 seconds or more.
(f) Preform steps (d) to (e) 11 times.
HINT:

During performing the steps (d) to (e) 11 times, drive the vehicle at over 65 km and make the fuel cut
happen for over 3 sec.

If a malfunction exists, the MIL will be indicated on the multi information display during step (f).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a hand±held tester, turn the ignition switch OFF after performing steps (c) to (f),
then perform steps (c) to (f) again.
DI6V6±02

DI±60
± 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 Are there any other codes (besides DTC P0136) being output?
YES Go to relevant DTC chart.
NO
2 Check for open and short in harness and connector between ECM and oxygen
sensor (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check output voltage of oxygen sensor.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up the engine to normal operating temp.
CHECK:
Read voltage output of oxygen sensor when engine suddenly raced.
HINT:
Perform a quick racing of 2,000 rpm or more 3 times by using the accelerator pedal.
OK:
Oxygen sensor output voltage: Alternates from 0.40 V or less to 0.50 V or more.
OK Check that each connector is properly con-
nected.
NG
Replace oxygen sensor.

DI±62
± 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 air induction system (See page SF±1).
NG Repair or replace.
OK
2 Check injector injection (See page SF±12).
NG Replace injector.
OK
3 Check mass air flow meter and engine coolant temp. sensor
(See page SF±22 and SF±49).
NG Repair or replace.
OK
4 Check for spark and ignition (See page IG±1).
NG Repair or replace.
OK

P18349
± DIAGNOSTICSENGINE
DI±63
2001 PRIUS (RM778U)
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump and fuel pipe line.
OK
6 Check gas leakade on exhaust system.
NG Repair or replace.
OK
7 Check the output voltage of heated oxygen sensor during idling.
PREPARATION:
Warm up the oxygen sensor the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Use the OBD II scan tool or TOYOTA hand±held tester read the output voltage of the heated oxygen sensor
during idling.
OK:
Oxygen sensor output voltage:
Alternates repeatedly between less than 0.4 V and more than 0.55 V (See the following table).
OK Go to step 9.
NG

DI±64
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
8 Check for open and short in harness and connector between ECM and heated
oxygen sensor (See page IN±30).
NG Repair or replace harness or connector.
OK
Replace heated oxygen sensor.
9 Perform confirmation driving pattern (See page DI±50).
GO
10 Is there DTC P0171 being output again?
YES Check and replace ECM.
NO
11 Did vehicle runs out of fuel in the past?
NO Check for intermittent problems.
YES
DTC P0171 or P0172 is caused by running out
of fuel.

± 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.