TOYOTA PRIUS 2001 Service Repair Manual
PRIUS 2001
TOYOTA
TOYOTA
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TOYOTA PRIUS 2001 Service Repair Manual
Trending: cylinder bolt, trailer, inflation pressure, engine oil capacity, automatic transmission, door lock, odometer
Page 761 of 1943
± DIAGNOSTICSENGINE
DI±163
2001 PRIUS (RM778U)
OK Go to step 5.
NG
Check for open in harness and connector between EFI main relay and circuit opening relay (Mark-
ing: C/OPN), circuit opening relay and ECM (See page IN±41).
5 Check fuel pump (See page SF±6).
NG Repair or replace fuel tank assembly.
OK
6 Check for open in harness and connector between circuit opening relay and fuel
pump and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±41).
Page 762 of 1943
A14005B10046
A14006
ON
FC
Fuel Inlet Hose
OFF
ON
DI±164
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
OBD II scan tool (excluding TOYOTA hand±held tester):
1 Check operation of fuel pump.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
(a) Connect between terminal FC of the ECM connector and
body ground.
(b) Check for fuel pressure in the fuel inlet hose when it is
pinched off.
OK:
There is pressure in fuel inlet hose.
HINT:
At this time, you will hear a fuel return flowing noise.
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±22).
NG
2 Check for ECM power source circuit (See page DI±156).
NG Repair or replace.
OK
3 Check circuit opening relay (Marking: C/OPN) (See page SF±38).
NG Replace circuit opening relay.
OK
Page 763 of 1943
± DIAGNOSTICSENGINE
DI±165
2001 PRIUS (RM778U)
4 Check voltage between terminal FC of ECM and body ground
(See page DI±161).
OK Go to step 5.
NG
Check for open in harness and connector between EFI main relay and circuit opening relay (Mark-
ing: C/OPN), circuit opening relay and ECM (See page IN±41).
5 Check fuel pump (See page SF±6).
NG Repair or replace fuel tank assembly.
OK
6 Check for open in harness and connector between circuit opening relay and fuel
pump and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±41).
Page 764 of 1943

A14037
Combination MeterECM
Instrument Panel J/B
W
BatteryE10 IG1 Relay
6
J11
J/C IG1C11
C10
ID DC/DCG±R
2A
A 5
W
W±B
F114
3GAUGE
Ignition SW 22
2 3B±Y
21
2 1
1 1
MAINL
AM1
B±G4
FL Block No. 1FL Block No. 2 F1312D
2B 2K 2H
86 5
AM1
W±G
MIL
DI±166
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
MIL Circuit Malfunction
CIRCUIT DESCRIPTION
If the ECM detects trouble, the MIL lights up. At this time, the ECM records a DTC in memory.
HINT:
When the ignition switch is ON and ºREADYº indicator light is OFF, the bulb check of the ºMILº is performed
(ºMILº is ON).
When ºMILº is ON, but the DTC of the engine is not memorized, it may be because of HV control system
abnormality, so check HV control system beforehand.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Troubleshoot in accordance with the chart below for each trouble symptom.
MIL does not light up
Start inspection from step 1 in case of using TOYOTA hand±held
tester and start from step 2 in case of not using TOYOTA hand±
held tester
MIL remains on
After inspection of step 3, start inspection from step 4 in case of
using TOYOTA hand±held tester and start from step 5 in case of
not using TOYOTA hand±held tester
DI6MN±03
Page 765 of 1943
± DIAGNOSTICSENGINE
DI±167
2001 PRIUS (RM778U)
1 Inspect diagnosis (normal mode, check mode) (See page DI±3).
OK Check and replace ECM (See page IN±41).
NG
2 Check MIL.
See combination meter troubleshooting on page BE±2.
NG Repair or replace bulb or combination meter as-
sembly.
OK
3 Check that ECM connectors are securely connected to ECM.
NO Connect connector to ECM.
YES
Check for open circuit in harness and connector between combination meter and ECM (See
page IN±41).
4 Check operation of MIL (See step 1).
OK Check and replace ECM (See page IN±41).
NG
Page 766 of 1943
DI±168
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
5 Is any DTC output?
Check DTC on page DI±14.
YES Repair circuit indicated by output code.
NO
6 Check IG1 relay (Marking: IG1).
NG Replace IG1 relay.
OK
Check for short circuit in harness and con-
nector between DLC3 and ECM (See page
IN±41).
Page 767 of 1943
A14038
W±B 13TC E9
TC
CG D2 DLC3
4P±B
Instrument Panel J/B6 2
2K 2D ID1
AECM
ID W±BA J24
J/CE
W±BP±B
J11
J/C J26 J/C
P±B
A E
W±B 8 8P±BJ16 J/C
C
C
F08565
CG
(±)
(+) ON
TC
± DIAGNOSTICSENGINE
DI±169
2001 PRIUS (RM778U)
TC Terminal Circuit
CIRCUIT DESCRIPTION
Terminal TC and CG are located in the DLC3. When connecting these terminals, DTCs in normal mode or
test mode can be read through the MIL flashing in the combination meter.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Even though terminal TC is not connected with terminal CG, the MIL blinks.
For the above phenomenon,an open or short in the wire harness, or malfunction inside the ECM is the
likely cause.
1 Check voltage between terminals TC and CG of DLC3.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals TC and CG of the
DLC3.
OK:
Voltage: 9 ± 14 V
OK Check and replace ECM (See page IN±41).
NG
DI7DL±02
Page 768 of 1943
DI±170
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
2 Check continuity between terminal CG of DLC3 and body ground.
NG Repair or replace harness or connector.
OK
3 Check for open and short circuit in harness and connector between ECM and
DLC3, and DLC3 and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±41).
Page 769 of 1943

FI7012A11860
P±G A/C Control Assembly
A8 E10522
ACTECM
± DIAGNOSTICSENGINE
DI±171
2001 PRIUS (RM778U)
A/C Cut Control Circuit
CIRCUIT DESCRIPTION
This circuit cuts air conditioning operation during vehicle acceleration in order to increase acceleration per-
formance. During acceleration with the vehicle speed at (AT: 25 km/h (16 mph), MT: 40 km/h (25 mph)) or
less, engine speed at (AT: 1,200 rpm, MT:1,600 rpm) or less and throttle valve opening angle at 60° or more,
the A/C magnet switch is turned OFF for several seconds.
WIRING DIAGRAM
INSPECTION PROCEDURE
TOYOTA hand±held tester:
1 Connect the TOYOTA hand±held tester and check operation of air conditioning
cut control.
PREPARATION:
(a) Connect the TOYOTA hand±held tester to the DLC3.
(b) Turn the ignition switch ON and TOYOTA hand±held tester main switch ON.
(c) Start the engine and air conditioning switch ON.
HINT:
A/C magnet clutch is turned ON.
(d) Select the ACTIVE TEST mode on the TOYOTA hand±held tester.
CHECK:
Check operation of A/C magnet clutch cut when air conditioning cut control is operated by the TOYOTA
hand±held tester.
OK:
A/C magnet clutch is turned OFF.
DI7T8±01
Page 770 of 1943
A14008
START
(±)
(+)ACT
DI±172
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
OK Proceed to next circuit inspection shown on
problem symptom table. (See page DI±22)
NG
2 Check for open and short in harness and connector between ECM and A/C am-
plifier. (See page IN±41)
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal ACT of ECM and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Start the engine.
CHECK:
Measure voltage between terminal ACT of ECM connector and
body ground when A/C switch is turned to ON and OFF.
OK:
A/C switch conditionVoltage
ON9 ± 14 V
OFFBelow 1.5 V
NG Check and replace A/C amplifier.
OK
Check and replace ECM. (See page IN±41)
Trending: windshield wipers, coolant temperature, check transmission fluid, high beam, change wheel, ECU, headlight bulb