TOYOTA PRIUS 2001 Service Repair Manual

I15477
Instrument Panel J/B
FL Block No. 2S3
Stop Light SW I15
Ignition SW
Engine Room J/BHybrid Vehicle
Control ECU
J25 ID1B±Y
ST1± IG2 AM2
1G±W
2
R±B2
H14
STP 1
H14 B±W
34
6 B±W
J24
B C B±W W±R
7
6
2
2C
15A AM21
2GW±R
9
1J 2
1B B
1
F12B±G
120A MAIN
Battery1
F13
1
F18J15
D J14
E G±W
Instrument Panel J/B
9
2K15A STOP
W
100A DC/DC
F11 1
2H
FL Block No. 1
1
F131
B±GS3
Stop Light SW J/C
J/C
FL Block No. 1
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±655
2001 PRIUS (RM778U)
WIRING DIAGRAM

I19096
ON
STP
(+) (±)
DI±656
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check that stop light comes on when brake pedal is depressed, and turns off when brake pedal is released.
NG Check stop light system (See page BE±2).
OK
2 Check voltage between terminal STP of hybrid vehicle control ECU connector
and body ground.
PREPARATION:
(a) Remove the hybrid vehicle control ECU with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal STP of hybrid vehicle con-
trol ECU connector and body ground, when the brake pedal is
depressed and released.
OK:
Depressed10 ± 14 V
ReleasedBelow 1 V
OK Proceed to next circuit inspection shown in
problem symptom table (See page DI±648).
NG

I19096
ON
ST1±
(+) (±)
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±657
2001 PRIUS (RM778U)
3 Check voltage between terminal ST1± of hybrid vehicle control ECU connector
and body ground.
PREPARATION:
(a) Remove the hybrid vehicle control ECU with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal ST1± of hybrid vehicle con-
trol ECU connector and body ground, when the brake pedal is
depressed and released.
OK:
DepressedBelow 1 V
Released10 ± 14 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±648).
NG
4 Check wire harness and connector between terminal STP of hybrid vehicle con-
trol ECU and stop light switch, and terminal ST1± of hybrid vehicle control ECU
and stop light switch (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace hybrid vehicle control
ECU (See page DI±174
).

± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±659
2001 PRIUS (RM778U)
Power source circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the hybrid vehicle control ECU.
WIRING DIAGRAM
See page DI±156.
INSPECTION PROCEDURE
1 Check IGN and EFI fuse.
CHECK:
Check continuity of IGN and EFI fuse.
OK:
Continuity
NG Replace the failure fuse.
OK
2 Check voltage between terminals IGSW, BATT and GND of hybrid vehicle control
ECU connector (See page IN±41).
PREPARATION:
(a) Turn ignition switch OFF.
(b) Disconnect the hybrid vehicle control ECU connector.
CHECK:
Measure voltage between terminals IGSW, BATT and GND
OK:
Voltage: 10 ± 14 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±648).
NG
DI7NJ±01

DI±660
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
3 Check wireharness and connector between hybrid vehicle control ECU and body
ground (See page IN±41).
NG Repair or replace wireharness or connector.
OK
Check and repair wireharness and connector
between hybrid vehicle control ECU and bat-
tery (See page IN±41
).

I15479
Combination Meter
FL Block No. 1Instrument Panel J/B
to Body ECU 5A AM1IG1
Relay
3
GR±B14
C10
2A
CRUISE 8
W±B
B±G22
C10 L
2K8
2
C11
W±B I15 Ignition SW
AM1
IG1
F11
Battery
ID 10A GAUGE
5
AJ11
J/C 2 1 2B6
2B3
2D6 W
W±G
B±Y
24
B±Y
1F13
1F18
1FL Block No. 2
120A MAIN
100A DC/DC7
2A
1
2H
IH BR
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±665
2001 PRIUS (RM778U)
CRUISE MAIN Indicator Light Circuit
CIRCUIT DESCRIPTION
When the cruise control main switch is turned ON, CRUISE MAIN indicator light lights up.
WIRING DIAGRAM
DI7NL±01

DI±666
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check combination meter (See page BE±2).
NG Replace combination meter.
OK
Check and replace hybrid vehicle control
ECU (See page DI±174).

DI7XP±01
± DIAGNOSTICSCOMBINATION METER SYSTEM
DI±669
2001 PRIUS (RM778U)
PRE±CHECK
1. BEFORE CHECK
Since a trouble symptom may result from multiple causes, check not only the part where a user complains
of but also the following items in order to be sure no other trouble is identified.

Fuse related parts

Wire harness related parts

Valve related parts
NOTICE:

Setting the ignition switch to START temporarily stops all meter operation, however, this is not
an error.

When replacing the combination meter ECU, carefully avoid any contact with the IC.

Removing a battery terminal during engine operation may cause a reversed current and lead
to malfunction.

When disconnecting any connector or terminal, be sure to disconnect the battery terminal.

Flashing pattern No.1
Flashing pattern No.2
0.6 sec. 0.6 sec.
0.3 sec. 0.3 sec. 1.2 sec. ON
OFF ON
OFF
0.3 sec.
DI±670
± DIAGNOSTICSCOMBINATION METER SYSTEM
2001 PRIUS (RM778U)
2. FUEL GAUGE DIAGNOSIS CHECK
(a) Fuel emergency display
HINT:
If FR voltage input to the fuel sender gauge is abnormal (4.8 V or more, or 0.06 V or less) due to any error,
an emergency will be displayed.
(b) Display:
Immediately after the ignition switch is ON, all of the segments flash.
Diagnosis displayTrouble ItemPlausible Cause
All segments flashing
(Flashing pattern No. 1)
Cycle: 1.2 sec
Duty: 50 %Multiple communication errorCommunication is cut off.
4. Body ECU faulty
5. Engine ECU faulty
6. Open or short in wire harness for communica-
tion
HINT:
Referring to the attached reference material 1 or
2, specify the main cause
All segments flashing
(Flashing pattern No. 2)
(300 msec. ON, 300 msec OFF) x 2 + 1.2
sec. OFFSender gauge related trouble1. Sender gauge faulty
2. Open or short in wire harness
Display segments and ºEº flashing.
(Flashing pattern No. 1)
Cycle: 1.2 sec
Duty: 50 %Temperature sensor (located in the tank) related
trouble1. Temperature sensor faulty
2. Open or short in wire harness
Display segments and ºEº flashing.
(Flashing pattern No. 2)
(300 msec. ON, 300 msec. OFF) x 2 + 1.2
sec. OFFIndication sensor (located in the meter ) trouble1. Combination meter faulty
Segment No. 1 flashing
(Flashing pattern No. 1)
Cycle: 1.2 sec
Duty: 50 %This does not mean any failure.
When a battery is connected, it continues flash-
ing until the volume is confirmed.This occurs when the battery is turned ON.
HINT:
Low fuel warning: Cycle: 0.6 sec.;
Duty: 50 %

DI7XR±01
I17803
Connector ºAº Connector ºBº
(LHD model) COMBINATION METER DI±672
± DIAGNOSTICSCOMBINATION METER SYSTEM
2001 PRIUS (RM778U)
TERMINALS OF ECU
Disconnect connector ºAº and ºBº from the combination meter and inspect the connectors on the wire har-
ness side as shown in the table.
Tester connectionConditionSpecified condition
A1 ± Ground
(ILL ± Body ground)Ignition switch ON and tail cancel switch ON or
OFFBelow 1V or 4.5 ± 5.5 V
A2 ± Ground
(E ± Body ground)ConstantContinuity
A3 ± Ground
(OPO ± Body ground)Ignition switch ON and trip reset switch ON or
OFFBelow 1V or 4.5 ± 5.5 V
A9 ± Ground
(SI ± Body ground)Ignition switch ON and slowly turn drive wheelBelow 1V or 10 ± 14 V
A10 ± Ground
(LP ± Body ground)Ignition switch ON and ABS indicator ON or OFFBelow 1V or 10 ± 14 V
A11 ± Ground
(L ± Body ground)Ignition switch ONPulse generation
A13 ± GroundI iti it h ON d l l t d i h lBelow 1V or 10 ± 14 VA13 Ground
(+S ± Body ground)Ignition switch ON and slowly turn drive wheelBelow 1V or 4.5 ± 5.5 V
A14 ± Ground
(ES ± Body ground)ConstantContinuity
A15 ± Ground
(EP ± Body ground)ConstantContinuity
A16 ± Ground
(SW ± Body ground)Ignition switch ON and air bag indicator light ON
or OFFBelow 1V or 10 ± 14 V
A17 ± Ground
(S ± Body ground)Headlight dimmer switch Hi or LowBelow 1V or 10 ± 14 V
A18 ± Ground
(B ± Body ground)Ignition switch ON and turn signal switch rightBelow 1V or 10 ± 14 V
A19 ± Ground
(B ± Body ground)Ignition switch ON and turn signal switch leftBelow 1V or 10 ± 14 V
A21 ± Ground
(B ± Body ground)Constant10 ± 14 V
A22 ± Ground
(IG ± Body ground)Ignition switch OFF or ONBelow 1V or 10 ± 14 V