2001 TOYOTA PRIUS engine coolant

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

± 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

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.

± 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±154
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
2 Check remaining amount of fuel.
NG Supply fuel.
OK
3 Check air induction system (See page SF±1).
NG Repair or replace.
OK
4 Check for umusual noise or vibration when starting engine or racing.
NG Repair or replace.
OK
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump and fuel pipe line
(See page SF±19).
OK
6 Check air flow meter (See page SF±22) and engine coolant temp. sensor
(See page SF±49).
NG Repair or replace.
OK

Engine ECU
TROUBLE CODE
CALC LOAD
ENGINE SPD
COOLANT TEMP
INTAKE AIR
VEHICLE SPD
SHORT FT #1
LOND FT #1
FUEL SYS #1
FUEL SYS #2
ENG RUN TIME
BATTERY
INJECTOR
INJ VOL FB
FEL FB COEF
A/F LEARN
PURGE LEARN
KCS FEEDBACK
REQ ENQ TORQ
RAM MONITOR
ENG RUN SIG
ACC RACING SIG
ENG WARM UP SIG
ENG RUN PERM
FC STATUS
ENG STP LIMIT%
rpm
%
%
V
ms
%
%
degree
KW
ON / OFF
ON / OFF
ON / OFF
EMPS ECU
TROUBLE CODE
TRQ1
TRQ2
WRR
WRL
MOTOR ACTUAL
COMMAND VALUE
STR ANGL VEL
THERMISTOR TEMP
PIG SUPPLY
IG SUPPLY
TRQ1 ZERO VAL
TRQ2 ZERO VALV
V
V V V A
A
deg/s
ON / OFF°F ( °C)
°F ( °C)
mph ( km/h)
mph ( km/h)
mph ( km/h)
°F ( °C) DI±186
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±193
2001 PRIUS (RM778U)
5. CHECK FOR INTERMITTENT PROBLEMS
(a) Perform a simulation test (See page IN±41).
In the simulation test, reproduce the driving condition at the trouble occurrence according to the cus-
tomer 's comments and freeze frame data recorded with DTC, such as an opening angle of the acceler-
ator pedal, SOC, engine coolant temperature, engine rpm, and MG/1MG2 rpm and torque.
(b) Check the connector and terminal (See page IN±41).
(c) Handle the connector (See page IN±41).
6. TOYOTA HAND±HELD TESTER DISPLAY ITEMS
TOYOTA Hand±held tester displayMeasurement Item
1 BEF LATST ORNumber of operation of 1 trip before last
1 BEF LATST TRPNumber of trips before last
2 BEF LATST ORNumber of operation 2 trips before last
2 BEF LATST TRPNumber of trips 2 before last
ABNML CON BR±HVCommunication malfunction between HV ECU and brake
ACC SENSOR MAINMain accelerator sensor
ACC SENSOR SUBSub accelerator sensor
ACC TENT TRBLETentative trouble of accelerator
ACC THROTTLEAccelerator throttle
ACCEL MODEHistory of acceleration and reduction
AIR CON REQUESTAir conditioner request
AUX. BATT LOWAuxiliary battery becomes week
AUX. BATT VVoltage of auxiliary battery
BATT HIGH TEMPTemperature of the battery is too high
BATT HIGH VOLTVoltage of the battery is too high
BATT LOW BOLTVoltage of the battery is low
BATT OVER LOADBattery is overloaded
BATT SAVE RQSTRequest to save the main battery
BATTERY FULLBattery full
BRAKE TORQBrake torque
CELL TEMP±MAXHighest temperature of all battery cells
CELL TEMP±MINLowest temperature of all battery cells
CHG RESTRICTIONCharge restriction
COOLANT TEMPWater temperature
CRUISE CONTROLCondition of the cruise control
DC/DC CONV STOPDC/DC converter stop signal
DC/DC CONV STOPFactors causing DC/DC converter to stop
DC/DC STOP FACTDC/DC converter has stopped at least once
DC/DC V UNSETDC/DC voltage is unsettled
DCHG RQST SOCDischarge request to adjust SOC
DISCHAG INHIBITBattery is inhibited to discharge

DI7S2±01
DI±874
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
DIAGNOSTIC TROUBLE CODE CHART
DTC No.
(See Page)Detection ItemTrouble Area
11*1
(DI±876)Room temp. sensor circuit

Room temp. sensor

Harness or connector between room temp. sensor and A/C
amplifier

A/C amplifier
12*2
(DI±879)Ambient temp. sensor circuit

Ambient temp. sensor

Harness and connector between ambient temp. sensor and
ECM

ECM

Harness and connector between ECM and A/C amplifier

A/C amplifier
13
(DI±882)Evaporator temp. sensor circuit

Evaporator temp. sensor

Harness and connector between evaporator temp. sensor
and A/C amplifier

A/C amplifier
14
(DI±885)Engine coolant temp. sensor circuit

Water temp. sensor

Harness and connector between engine coolant temp. sensor
and ECM

ECM

Harness and connector between ECM and A/C amplifier
21*3
(DI±888)Solar sensor circuit

Solar sensor

Harness or connector between room temp. sensor and A/C
amplifier

A/C amplifier
22*4
(DI±891)
All conditions below are detected for 3 sec. or more
(g) Engine speed: 500 rpm or more
(h) Ratio between engine and compressor rpm deviates 20 %
or more in comparison to normal operation
Compressor drive belt

Compressor lock sensor

Compressor

Harness and connector between compressor lock sensor and
A/C amplifier
23
(DI±894)
Open in pressure switch circuit
Abnormal refrigerant pressure
[below 196 kPa (2.0 kgf/cm
2, 28 psi) over
3,140 kPa (32.0 kgf/cm2, 455 psi)]

Pressure switch

Harness or connector between pressure switch and A/C am-
plifier

A/C amplifier
31
(DI±897)Air mix damper position sensor circuit

Air mix control servomotor

Harness or connector between air mix control servomotor
and A/C amplifier

A/C amplifier
32
(DI±900)Air inlet damper position sensor circuit

Air inlet control servomotor

Harness or connector between air inlet control servomotor
and A/C amplifier

A/C amplifier
33
(DI±903)Air outlet damper position sensor circuit

Air outlet control servomotor

Harness or connector between air outlet control servomotor
and A/C amplifier

A/C amplifier
41
(DI±906)Air mix control servomotor circuit

Air mix control servomotor

Air mix damper position sensor

Harness or connector between air mix control servomotor
and A/C amplifier

A/C amplifier