2001 TOYOTA PRIUS relay

BE16S±02
BE±2
± BODY ELECTRICALTROUBLESHOOTING
1669 Author: Date:
2001 PRIUS (RM778U)
TROUBLESHOOTING
PROBLEM SYMPTOMS TABLE
IGNITION SWITCH:
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Ignition switch is not set to each position.3. Ignition switch
4. Power source circuitBE±17
±
KEY UNLOCK WARNING SWITCH:
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Key unlock warning system does not operate.
(The buzzer sounds when the ignition key is ACC or ON)
1. Ignition Switch
2. Key Unlock Warning Switch
3. Wire Harness
4. Body ECU
5. Combination MeterBE±17
BE±17
±
±
±
HEADLIGHT AND TAILLIGHT SYSTEM:
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Auto turn±off system does not operate when the driver's door is
opened.1. Drivers Door Courtesy Switch
2. Body ECUBE±27
DI±678
Auto turn±off system:
Headlight and taillight do not come on.1. Body ECU
2. Wire HarnessDI±678
±
Auto turn±off system:
Headlight and taillight stay on.1. Body ECU
2. Wire HarnessDI±678
±
w/o Daytime Running Light System:
SymptomSuspect AreaSee page
Only one headlight comes on.1. Bulb
2. Wire Harness±
±
ºLO±Beamº does not light (All).1. Headlight Control Relay
2. Wire HarnessBE±20
±
ºLO±Beamº does not light (One side).
1. Bulb
2. HEAD LH Fuse
3. HEAD RH Fuse
4. Wire Harness±
BE±12
BE±12
±
ºHI±Beamº does not light (All).1. Headlight Dimmer Switch
2. Wire HarnessBE±20
±
ºHI±Beamº does not light (One side).
1. Bulb
2. HEAD LH Fuse
3. HEAD RH Fuse
4. Wire Harness±
BE±12
BE±12
±
ºFlashº does not light.
1. HEAD LH Fuse
2. HEAD RH Fuse
3. Headlight Dimmer Switch
4. Wire HarnessBE±12
BE±12
BE±20
±
ºFlashº does not light.1. Bulb
2. Wire Harness±
±

± BODY ELECTRICALTROUBLESHOOTING
BE±3
1670 Author: Date:
2001 PRIUS (RM778U) Headlight does not come on.
1. Headlight Control Relay
2. Wire HarnessBE±20
±
Headlight does not come on.1. Bulb
2. Wire Harness±
±
Headlight flickers.1. Bulb
2. Wire Harness±
±
Headlight is dark.1. Bulb
2. Wire Harness±
±
Only one taillight comes on.1. Bulb
2. Wire Harness±
±
Taillight does not come on.
(Headlight is normal)
1. TAIL Fuse
2. Taillight Control Relay
3. Light Control Switch
4. Wire HarnessBE±12
BE±42
BE±20
±
Taillight does not come on.
(Headlight does not light)1. Light Control Switch
2. Wire HarnessBE±20
±
w/ Daytime Running Light System:
SymptomSuspect AreaSee page
Only one headlight comes on.
1. Daytime Running Light Relay
2. Daytime Running Light Main Relay
3. Bulb
4. Wire HarnessBE±20
BE±20
±
±
ºLO±Beamº does not light (All).1. Headlight Control Relay
2. Wire HarnessBE±20
±
ºLO±Beamº does not light (One side).
1. Bulb
2. HEAD LO (LH) Fuse
3. HEAD LO (RH) Fuse
4. Wire Harness±
BE±12
BE±12
±
ºHI±Beamº does not light (All).
1. Headlight Dimmer Switch
2. Daytime Running Light Main Relay
3. Combination MeterBE±20
BE±20
±
ºHI±Beamº does not light (One side).
1. Bulb
2. HEAD HI (LH) Fuse
3. HEAD HI (RH) Fuse
4. Daytime Running Light No.2 Relay
5. Wire Harness±
BE±12
BE±12
BE±20
±
ºFlashº does not light.
1. Headlight Dimmer Switch
2. Daytime Running Light Main Relay
3. Wire HarnessBE±20
BE±20
±
Headlight does not come on.
1. Headlight Control Relay
2. Daytime Running Light Main Relay
3. Daytime Running Light No.2 Relay
4. Headlight Dimmer Switch
5. Light Control Switch
6. Body ECU
7. Wire Harness
8. BulbBE±20
BE±20
BE±20
BE±20
BE±20
DI±678
±
±
Headlight does not come on with light control switch in HEAD.
1. Light Control Switch
2. Body ECU
3. Wire HarnessBE±20
DI±678
±
Headlight does not go out with light control switch in OFF.
1. Headlight Control Relay
2. Body ECU
3. Wire HarnessBE±20
DI±678
±

BE±4
± BODY ELECTRICALTROUBLESHOOTING
1671 Author: Date:
2001 PRIUS (RM778U) Headlight flickers.
1. Bulb
2. Wire Harness±
±
Headlight is dark.1. Bulb
2. Wire Harness±
±
Taillight does not come on with light control switch in TAIL.1. Taillight Control Relay
2. Wire HarnessBE±20
±
Taillight does not go out with light control switch in OFF.1. Taillight Control Relay
2. Wire HarnessBE±20
±
Headlight does not come on with engine running and light control
switch in OFF.
1. ECU±B Fuse
2. GAUGE Fuse
3. Daytime Running Light Main Relay
4. Daytime Running Light Relay
5. Alternator L Terminal
6. Body ECU
7. Parking Brake Switch
8. Wire HarnessBE±12
BE±12
BE±20
BE±20
±
DI±678
BE±42
±
TURN SIGNAL AND HAZARD WARNING SYSTEM
SymptomSuspect AreaSee page
ºHazardº and ºTurnº do not light up.
1. GAUGE Fuse
2. TURN HAZ Fuse
3. Ignition Switch
4. Turn Signal Flasher Relay
5. Wire HarnessBE±12
BE±12
BE±17
BE±25
±
Hazard warning light does not light up.
(Turn is normal)1. Hazard Warning Switch
2. Wire HarnessBE±25
±
Turn signal does not light up.
(Hazard is normal)1. Turn Signal Switch
2. Wire HarnessBE±25
±
Turn signal does not light up in one direction.1. Turn Signal Switch
2. Wire HarnessBE±25
±
Only one bulb does not light up.1. Bulb
2. Wire Harness±
±
INTERIOR LIGHT SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
All the lights do not come ON.DOME FuseBE±12
The driver door courtesy light does not come ON when the
driver's door is opened.1. Driver's Door Courtesy Switch
2. Wire Harness
3. Body ECUBE±27
±
±
The passenger door courtesy light does not come ON when the
passenger's door is opened.1. Passenger's Door Courtesy Switch
2. Wire Harness
3. Body ECUBE±27
±
DI±678
The room light does not come on when the rear±right door is
opened.
1. Rear±Right Door Courtesy Switch
2. Wire Harness
3. Body ECU
4. Room LightBE±27
±
DI±678
±
The room light does not come on when the rear±left door is
opened.
1. Rear±Left Door Courtesy Switch
2. Wire Harness
3. Body ECU
4. Room LightBE±27
±
DI±678
±
Only one of the bulbs comes ON.Bulb±

± BODY ELECTRICALTROUBLESHOOTING
BE±5
1672 Author: Date:
2001 PRIUS (RM778U) The illumination does not fade out when all the doors are closed.
1. Courtesy Switch
2. Wire Harness
3. Body ECUBE±27
±
DI±678
The illumination does not fade out immediately when the ignition
switch is turned to ACC or ON within 15 seconds after all the
doors are closed.
1. Ignition Switch
2. ECU±B Fuse
3. GAUGE Fuse
4. Wire Harness
5. Body ECUBE±17
BE±12
BE±12
±
DI±678
The illumination does not fade out immediately when all the doors
are locked within 15 seconds after they are closed.1. Door Unlock Detection Switch
2. Wire Harness
3. Body ECUBE±62
±
DI±678
Interior light does not light up.
(in front personal light)1. Bulb
2. Personal Light
3. Wire Harness±
BE±27
±
Front personal light does not light up.
1. Bulb
2. Personal Light
3. Wire Harness±
BE±27
±
Rear personal light does not light up.
1. Bulb
2. Interior Light
3. Wire Harness±
BE±27
±
Luggage compartment light does not light up.
1. Bulb
2. Luggage Compartment Door Courtesy Switch
3. Wire Harness±
BE±27
±
Courtesy light does not light up.
1. Bulb
2. Door Courtesy Switch
3. Wire Harness
4. Body ECU±
BE±27
±
DI±678
BACK±UP LIGHT SYSTEM
SymptomSuspect AreaSee page
Back±Up Light does not light up.
1. GAUGE Fuse
2. Ignition Switch
3. Back±up Light Relay
4. Wire Harness
5. BulbBE±12
BE±17
BE±30
±
±
Back±Up Light remains always on.1. Bulb
2. Wire Harness±
±
Only one light does not light up.1. Bulb
2. Wire Harness±
±
STOP LIGHT SYSTEM
SymptomSuspect AreaSee page
Stop light does not light up.
1. STOP Fuse
2. Stop Light Switch
3. Wire HarnessBE±12
BE±32
±
Stop light always lights up.1. Stop Light Switch
2. Wire HarnessBE±32
±
Only one light always lights up.Wire Harness±
Only one light does not light up.1. Bulb
2. Wire Harness±
±

BE±8
± BODY ELECTRICALTROUBLESHOOTING
1675 Author: Date:
2001 PRIUS (RM778U) Shift position indicator light does not light up.
1. ECM
2. Shift Position Sensor
3. HV ECU
4. Meter Circuit Plate
5. Wire Harness±
HT±54
±
BE±39
±
CRUISE indicator light does not light up.
1. Bulb
2. HV ECU
3. Meter Circuit Plate
4. Wire Harness±
±
BE±39
±
DEFOGGER SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Rear window defogger does not operate.
1. DEF M±Fuse
2. Defogger Relay
3. Defogger Switch (in A/C Amplifier)
4. Defogger Wire
5. Wire Harness
6. Body ECU
7. Noise Filter
8. A/C ECUBE±12
BE±49
DI±864
BE±49
±
DI±678
±
DI±864
Mirror heater does not operate.
1. M±HTR Fuse (Passenger SIde J/B)
2. Mirror Heater Relay
3. Mirror Heater
4. Wire HarnessBE±12
BE±49
BE±49
±
POWER WINDOW CONTROL SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Power window dose not operate.
1. ECU B Fuse
2. GAUGE Fuse
3. Power Main Relay
4. Ignition Switch
5. Power Window Master Switch
6. Body ECU
7. Wire HarnessBE±12
BE±12
BE±56
BE±17
BE±56
DI±678
±
Only the driver's window does not operate.
1. Power Window Master Switch
2. Power Window Switch
3. Power Window Motor
4. Wire HarnessBE±56
BE±56
BE±56
±
ºWindow lock functionº does not operate.Power Window Master SwitchBE±56
Illumination does not light up.Power Window Master SwitchBE±56

± BODY ELECTRICALTROUBLESHOOTING
BE±9
1676 Author: Date:
2001 PRIUS (RM778U)
POWER DOOR LOCK CONTROL SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
All the doors cannot be locked or unlocked.
(Power Window Control System is normal.)1. Door Lock Control Switch
2. Body ECU
3. Wire HarnessBE±62
DI±678
±
Only one side door lock control does not operate.1. Door Lock Motor
2. Wire HarnessBE±62
±
Door key related function does not operate.
1. Door Key Lock and Unlock Switch
2. Body ECU
3. Wire HarnessBE±62
DI±678
±
Key confinement prevention function does not operate.
1. Key Unlock Warning Switch
2. Door Courtesy Switch
3. Body ECU
4. Wire HarnessBE±17
BE±27
DI±678
±
THEFT DETERRENT SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
HINT:
Troubleshooting of the theft deterrent system is based on the premise that the door lock control system is
operating normally. Accordingly, before troubleshooting the theft deterrent system, first make certain that
the door lock control system is operating normally.
SymptomSuspect AreaSee page
The theft deterrent system cannot be set
1. Indicator light circuit
2. ECU power source circuit
3. Key unlock warning switch circuit
4. Door key lock and unlock switch circuit
5. Door courtesy switch circuit
6. Door unlock detection switch circuit
7. Engine hood courtesy switch circuitDI±704
DI±685
DI±695
DI±724
DI±714
DI±710
DI±720
The indicator light does not blink when system is set.Indicator light circuitDI±704
When the system is set
(The system does not operate when the rear door is unlocked).Door unlock detection switch circuitDI±710
When the system is set
(The system does not operate when the luggage compartment
door is opened by a method other than the key).
Luggage compartment door courtesy switch circuitDI±722
When the system is set
(The system does not operate when the engine hood is lifted).Engine hood courtesy switch circuitDI±720
While the system is in warning operation
(Horns do not sound).Horn relay circuitDI±697
While the system is in warning operation
(Headlights do not flash).Headlight control relay circuitDI±693
While the system is in warning operation
(Taillights do not flash).Taillight control relay circuitDI±691
While the system is in warning operation
(The door lock is not locked).Door unlock detection switch circuitDI±710
System is still set even when a rear door is openDoor courtesy switch circuitDI±714
Even when the system is not set
(Horns sound).Horn relay circuitDI±697

BE±10
± BODY ELECTRICALTROUBLESHOOTING
1677 Author: Date:
2001 PRIUS (RM778U) Even when the system is not set
(Headlights stay on).
Headlight control relay circuitDI±697
Even when the system is not set
(Taillights stay on).Taillight control relay circuitDI±691
WIRELESS DOOR LOCK CONTROL SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
HINT:
Troubleshooting of the wireless door lock control system is based on the premise that the door lock
control system is operating normally. Accordingly, before troubleshooting the wireless door lock control
system, first make certain that the door lock control system is operating normally.
If the trouble still reappears even though there are no abnormalities in any of the other circuits, then
check and replace the Wireless Door Lock Control Receiver as the last step.
SymptomSuspect AreaSee page
All functions of wireless door lock control system do not operate.
1. Transmitter
2. Wireless Door Lock Control Receiver
3. Wire Harness
4. Body ECUBE±83
BE±83
±
DI±678
POWER MIRROR CONTROL SYSTEM
SymptomSuspect AreaSee page
Both right and left mirrors do not operate.
1. ACC Fuse
2. ACC Relay
3. Mirror Switch
4. Wire HarnessBE±12
BE±12
BE±93
±
Only one side of mirror does not operate.1. Mirror Motor
2. Wire HarnessBE±93
±
AUDIO SYSTEM
SymptomSuspect AreaSee page
Audio system abnormal operation.TROUBLESHOOTINGBE±97
CLOCK SYSTEM
SymptomSuspect AreaSee page
Clock will not operate.TROUBLESHOOTING NO.1BE±102
Clock loses or gains time.TROUBLESHOOTING NO.2BE±102
HYBRID BEHICLE IMMOBILIZER SYSTEM
SymptomSuspect AreaSee page
Hybrid vehicle immobilizer system does not operate.Pre±checkBE±111

± BODY ELECTRICALTROUBLESHOOTING
BE±11
1678 Author: Date:
2001 PRIUS (RM778U)
HORN SYSTEM
SymptomSuspect AreaSee page
Horn system does not operate.
1. HORN Fuse
2. Horn Relay
3. Horn Switch
4. Horn
5. Wire HarnessBE±12
BE±117
BE±117
BE±117
±
Horns blow all the time.
1. Horn Relay
2. Horn Switch
3. Wire HarnessBE±117
BE±117
±
One horn operates but the other horn does not operate.1. Horn
2. Wire HarnessBE±117
±
Horns operate abnormally.
1. Horn Relay
2. Horn
3. Wire HarnessBE±117
BE±117
±