engine TOYOTA PRIUS 2001 Service Repair Manual

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 %

DI±682
± DIAGNOSTICSCOMBINATION METER SYSTEM
2001 PRIUS (RM778U)
4 Check the corresponding switch or ECU.
CHECK:
Check if the corresponding switch or ECU is normal or not.
Ye s
No Corresponding switch or ECU faulty.
Combination meter ECU faulty.
*:
Multiplex communication inputSingle Communication Input
OPEN DOOR WARNINGHI±BEAM INDICATOR
BRAKE WARNINGTURN SIGNAL IND
OUTPUT CONTROL INDICATORSRS WARNING
SHIFT POSITION INDICATORABS WARNING
SEAT BELT WARNINGCHECK ENGINE WARNING
READY INDICATOR
WATER TEMPERATURE WARNING
OIL PRESSURE WARNING
CRUISE CONTROL INDICATOR
TAIL INDICATOR
DISCHARGE WARNING

DI7NN±01
I15530
B9 B8
DI±686
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
TERMINALS OF ECU
BODY ECU
Symbols (Terminals No.)Wiring ColorConditionSTD Voltage (V)
FLD e E GBWBPower window (FR LH) is not operatingBelow 1 vFLD e E
(B8±2 ± B9±1)G - B e W ± BPower window (FR LH) is operating downward10 ± 14 v
FLU e E RWWBPower window (FR LH) is not operatingBelow 1 vFLU e E
(B8±3 ± B9±1)R ± W e W ± BPower window (FR LH) is operating upward10 ± 14 v
LUG e E LBWBLuggage compartment door key lock and unlock switch is ONBelow 1 vLUG e E
(B8±5 ± B9±1)L ± B e W-BLuggage compartment door key lock and unlock switch is OFF10 ± 14 v
RX (B8±6)YAVC ± LAN communication circuit±±
PRG (B8±7)B ± RWireless door lock ECU communication circuit±±
RDA (B8±8)LWireless door lock ECU communication circuit±±
HR e E BRWBHorn switch is ONBelow 1 vHR e E
(B8±10 - B9±1)B ± R e W- BHorn switch is OFF10 ± 14 v
BDR ± ± Body ground
(B8±11 - Body ground)W ± L e
Body groundConstant10 ± 14 v
PCTY e E RWWBPassenger door courtesy switch is OFFBelow 1 vPCTY e E
(B8±12 - B9±1)R ± W e W - BPassenger door courtesy switch is ON10 ± 14 v
HCTY e E RWWBEngine hood courtesy switch is OFFBelow 1 vHCTY e E
(B8±13 - B9±1)R ± W e W - BEngine hood courtesy switch is ON10 ± 14 v
LCTY e E RLWBLuggage door courtesy switch is OFFBelow 1 vLCTY e E
(B8±14 - B9±1)R ± L e W - BLuggage door courtesy switch is ON10 ± 14 v
MPX+ (B8±15)GR ± BMultiplex communication circuit±±
MPX± (B8±16)GRMultiplex communication circuit±±
LSWP e E WWBPassenger door unlock detection switch OFF (door unlocked)Below 1 vLSWP e E
(B8±17 - B9±1)W e W - BPassenger door unlock detection switch ON (door locked)10 ± 14 v
LSR e E WLWBRear door unlock detection switch OFF (door unlocked)Below 1 vLSR e E
(B8±18 - B9±1)W ± L e W - BRear door unlock detection switch ON (door locked)10 ± 14 v
SH e E BWWBTheft deterrent system is not operatingBelow 1 vSH e E
(B8±20 - B9±1)B ± W e W - BTheft deterrent system is operating10 ± 14 v
E ± Body ground
(B9±1 - Body ground)W ± B e
Body groundConstantBelow 1 v

I15484
2 3 66
8 7
1 4 2
1
4
3 2 1 1
11
1
710
883
A L D
FE
E
E
LE
ER±L
R±G
R±W
R±G R±W R±W R±W
R±G
R±G B±G
R±G B
F13 F12
2I
2A 1B1F
1F
1F3
ID2 IA2J20
J/C
IA1
J4J5
ID 2K 2A
15
17
BatteryC10 High Beam
Indicator Light
(Comb. meter) F18
FL Block No. 2
J11
J/CJ4 H2
Headlight RH
10A HEAD (LH) 10A HEAD (RH)
Short Pin HEAD RelayEngine Room J/BB9
Body ECU
Short Pin
120A MAIN
Instrument
Panel J/BJ12 J13
W±B
H1
Headlight
LH
1
FL Block No. 13
1
HRLY
Instrument
Panel J/B DI±698
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
Headlight Relay Circuit
CIRCUIT DESCRIPTION
Head light relay will be ºONº by operating the headlight switch. The transistor which activates the headlight
relay has two sorts: one activates directly by the headlight switch for fail safe and the other activates by CPU.
the one that activates by CPU has two systems and prevents the headlight from turning off at the time of
one system trouble in the automatic operation circuit.
When the theft deterrent system is activated, it causes the transistor in the ECU to switch ON and OFF at
approximately 0.25 sec. intervals. This switches the headlight control relay ON and OFF, thus flashing the
headlights (See the wiring diagram below).
In this condition, if any of the following operations is done, the transistor in the ECU goes OFF and the head-
light control relay switches OFF, thus stopping the headlights flashing:
(1) Unlock the front LH or RH door with a key.
(2) Turn the ignition switch to ACC or ON position.
(3) Unlock the doors with the wireless door lock control system.
(4) Wait for approximately 60 seconds.
WIRING DIAGRAM
DI5VQ±04

I15492
B8BODY ECU
HR 10
Battery10A
HORNHorn Relay
2 13 5 Engine Room J/B
C14
Horn SW
(Comb. SW)
6 1
1
1 B229
D DB±R B±R
B±R
B±W
B±R
H4
Horn F18
FL Block No. 2
120A MAINB±G
F13 F121J 1F
1BID24
J20
J/C FL Block No. 1
1IA28
B±R DI±702
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
Horn Circuit
CIRCUIT DESCRIPTION
The horn is connected to the body ECU and activated by the body ECU.
WIRING DIAGRAM
DI2A3±06

I15508
Body ECU
Engine Room J/B
Instrument Panel J/B
F18 Fusible Link Block No.2
J/C
120A MAIN FL
Battery L6
Luggage
Compartment
Light SW L5
Luggage
Compartment
LightI16 Interior Light
P4 Front Personal Light7
22N1
R±B 1 2
L±Y J29E
J30DJ/C
L±Y
W±B
L±Y
L±Y
2M3
2G2
L±Y1J 715A DOME
1B2
B
W±B B BJ/C
BI 11 J30D
J29E
1
F131
F12Instrument Panel J/B
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±707
2001 PRIUS (RM778U)
Illumination circuit
CIRCUIT DESCRIPTION
Receiving the courtesy signal from either of the door ECU, the Body ECU will make the interior light, ignition
light, and foot light come on.
WIRING DIAGRAM
DI6LX±03

I15497
1 21013Body ECU
HCTY B8
IE1
A A
AJ7
J/C
R±W
W±B R±W
J1
J/C
IEE2
Engine Hood
Courtesy SW
W±B
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±725
2001 PRIUS (RM778U)
Engine Hood Courtesy Switch Circuit
CIRCUIT DESCRIPTION
The engine hood courtesy switch is built into the engine hood lock assembly and goes ON when the engine
hood is opened and goes OFF when the engine hood is closed.
WIRING DIAGRAM
DI7NV±01

I00298
1 (+)
2 (±)
DI±726
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check engine hood courtesy switch.
PREPARATION:
(a) Remove engine hood lock assembly.
(b) Disconnect engine hood courtesy switch connector.
CHECK:
Check continuity between terminals 1 and 2 when engine hood
lock is locked and unlocked.
OK:
Engine hood lockTester connectionSpecified condition
LOCK±No continuity
UNLOCK1 ± 2Continuity
NG Replace engine hood courtesy switch.
OK
2 Check harness and connector between body ECU and switch, switch and body
ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace body ECU (See page
IN±41).

DI2BM±11
I15588
P9 Power Window
Master SW
Instrument Panel J/B
J20
J/C5
1
IG CPUB
B L±Y 1
IG1
C4 W±R
R±L 3
IC1
8
IC1 L±Y L±YC
J25 B
J24 4
2D 2
2G
W±R
R±L
C
R±L 20A PWR1
5A AM1
I15 Ignition SwitchIG1 Relay
IG1 AM1
B±Y W±G11
2J
1
2H
3
2B
24
L±Y
6
2D12 3
510A GAUGE
10
2K
W
15A DOME
7
1J8
2K
Engine Room J/B
2
1BBFL Block No. 1
1
F11100A DC/DC
B±G
F18 FL Block No. 2
120A MAIN 1
F121
F13
1
Battery
ID IGA J11 J/C
W±B
J17 J/CW±B1
IC1
W±B9
E Instrument Panel J/B
AJ/C DI±740
± DIAGNOSTICSDRIVER DOOR CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT INSPECTION
Power source circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the driver door ECU.
WIRING DIAGRAM