2001 TOYOTA PRIUS warning light

RS0JO±06
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
RS±1
1600 Author: Date:
2001 PRIUS (RM778U)
SRS AIRBAG
PRECAUTION
CAUTION:

The PRIUS is equipped with SRS, which comprises a driver airbag, front passenger airbag and
side airbag. Failure to carry out service operations in the correct sequence could cause the SRS
to unexpectedly deploy during servicing, possibly leading to a serious accident. Further, if a
mistake is made in servicing the SRS, it is possible that the SRS may fail to operate when re-
quired. Before performing servicing (including removal or installation of parts, inspection or
replacement), be sure to read the following items carefully, then follow the correct procedures
described in the repair manual.

Work must be started 90 seconds after the ignition switch is turned to the ºLOCKº position and
the negative (±) terminal cable is disconnected from the battery.
(The SRS is equipped with a back±up power source so that if work is started within 90 seconds
from disconnecting the negative (±) terminal cable of the battery, the SRS may be deployed.)

Do not expose the steering wheel pad, front passenger airbag assembly, side airbag assembly,
airbag sensor assembly, front airbag sensor or side airbag sensor assembly directly to hot air
or flames.
NOTICE:

Malfunction symptoms of the SRS are difficult to confirm, so the DTCs become the most impor-
tant source of information when troubleshooting. When troubleshooting the SRS, always in-
spect the DTCs before disconnecting the battery.

Even in cases of a minor collision where the SRS does not deploy, the steering wheel pad, front
passenger airbag assembly, side airbag assembly, airbag sensor assembly, front airbag sen-
sor and side airbag sensor assembly should be inspected.
(See page RS±14, RS±28, RS±41, RS±53, RS±58 and RS±63)

Before repairs, remove the airbag sensor if shocks are likely to be applied to the sensor during
repairs.

Never use SRS parts from another vehicle. When replacing parts, replace them with new parts.

Never disassemble and repair the steering wheel pad, front passenger airbag assembly, side
airbag assembly, airbag sensor assembly, front airbag sensor or side airbag sensor assembly
in order to reuse it.

If the steering wheel pad, front passenger airbag assembly, side airbag assembly, airbag sen-
sor assembly, front airbag sensor or side airbag sensor assembly has been dropped, or if there
are cracks, dents or other defects in the case, bracket or connector, replace it with new one.

Use a volt/ohmmeter with high impedance (10 kW/V minimum) for troubleshooting the system's
electrical circuits.

Information labels are attached to the periphery of the SRS components. Follow the instruc-
tions on the notices.

After work on the SRS is completed, perform the SRS warning light check (See page DI±497).

When the negative (±) terminal cable is disconnected from the battery, the memory of the clock
and audio system will be canceled. So before starting work, make a record of the contents mem-
orized in the audio memory system. When work is finished, reset the audio systems as they
were before and adjust the clock. To avoid erasing the memory in each memory system, never
use a back± up power supply from outside the vehicle.

If the vehicle is equipped with a mobile communication system, refer to the precaution in the
IN section.

H15218
H15513
H15517
H15675
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
RS±3
2001 PRIUS (RM778U)
6. SRS WARNING LIGHT
The SRS warning light is located on the combination meter. It
goes on to alert the driver of trouble in the system when a mal-
function is detected in the airbag sensor assembly self±diagno-
sis. In normal operation conditions when the ignition switch is
turned to the ON position, the light goes on for about 6 seconds
and then goes off.
7. AIRBAG SENSOR ASSEMBLY
The airbag sensor assembly is mounted on the floor inside the
lower center finish panel. The airbag sensor assembly consists
of an airbag sensor, safing sensor, diagnosis circuit, ignition
control, drive circuit, etc. It receives signals from the airbag sen-
sor, front airbag sensor, side airbag sensor assembly and door
side airbag assembly and judges whether the SRS must be ac-
tivated or not. The airbag sensor assembly cannot be disas-
sembled.
8. FRONT AIRBAG SENSOR
The front airbag sensor is mounted inside each of the side
members. The sensor unit is a mechanical type. When the sen-
sor detects deceleration force above a predetermined limit,
contact is made in the sensor, sending a signal to the airbag
sensor assembly. The front airbag sensor cannot be disas-
sembled.
9. SIDE AIRBAG SENSOR ASSEMBLY
The side airbag sensor assembly is mounted in the LH and RH
center pillars. The side airbag sensor assembly consists of a lat-
eral deceleration sensor, safing sensor, diagnosis circuit, etc.
It sends signals to the airbag sensor assembly to judge whether
the SRS side airbag must be activated or not. The side airbag
sensor assembly cannot be disassembled.

R12076Airbag Sensor AssemblyDisconnection
Detection
PinSRS
Warning
Light
H01315
Terminal for Diagnosis
Disconnection Detection Pin
Half Connection
Complete Connection
Terminal for
Diagnosis
RS±6
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
2001 PRIUS (RM778U)
HINT:
The type of connector is shown in the diagram on the previous
page.
(3) Electrical Connection Check Mechanism
This mechanism electrically checks that connectors
are connected correctly and completely. The electri-
cal connection check mechanism is designed so
that the disconnection detection pin connects with
the diagnosis terminals when the connector hous-
ing lock is locked.
HINT:
The illustration shows connectors º1º, º2º and º3º in step 11.

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±
±

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±7
1674 Author: Date:
2001 PRIUS (RM778U)
Warning Lights:
COMBINATION METER
SymptomSuspect AreaSee page
Warning light do not light up. (Except Discharge, Open Door and
SRS)
1. GAUGE Fuse
2. Meter Circuit Plate
3. DC/DC converter
4. Wire Harness±
BE±39
±
±
Fuel Level warning light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Fuel Tank Assembly
4. Wire Harness±
BE±39
±
±
Low Oil Pressure warning light does not light up.
1. Bulb
2. Low Oil Pressure Warning Switch
3. Meter Circuit Plate
4. Wire Harness±
BE±42
BE±39
±
ABS warning light does not light up.
1. Bulb
2. ABS ECU
3. Wire Harness±
DI±351
±
Seat Belt warning light does not light up.
1. Bulb
2. Buckle Switch
3. Meter Circuit
4. Wire Harness±
BE±42
BE±42
±
Brake warning light does not light up.
1. Bulb
2. Parking Brake Switch
3. Brake Fluid Level Warning Switch
4. Meter Circuit Plate
5. Wire Harness±
BE±42
BE±42
BE±39
±
SRS Warning light does not light up.
1. Bulb
2. Airbag Sensor Assembly
3. Meter Circuit Plate
4. Wire Harness±
DI±495
BE±39
±
Open Door warning light does not light up.
1. DOME Fuse
2. Bulb
3. Door Courtesy Switch
4. Meter Circuit Plate
5. Wire Harness±
±
BE±27
BE±39
±
Indicator Lights:
COMBINATION METER
SymptomSuspect AreaSee page
High beam indicator light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Wire Harness
4. Headlight System±
BE±39
±
BE±20
Turn indicator light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Wire Harness
4. Turn Signal and Hazard Warning System±
BE±39
±
BE±25
Malfunction indicator light does not light up.
1. Bulb
2. ECM
3. Meter Circuit Plate
4. Wire Harness±
±
BE±39
±
Indicator lights do not light up. (Except Turn, Hi±beam and
security)1. GAUGE Fuse
2. Wire Harness±
±

± 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

BE1VS±02
I18849
Brake Master Cylinder

Brake Fluid Level Warning Switch
Combination Meter Assembly

Meter Circuit
Multi Display
Ignition Switch
Instrument Panel J/B

Body ECU

GAUGE Fuse
Stop Light Switch
Engine Room J/B

DOME Fuse
Seat Belt Buckle Switch
Occupant Detection
Sensor
± BODY ELECTRICALCOMBINATION METER
BE±37
1704 Author: Date:
2001 PRIUS (RM778U)
COMBINATION METER
LOCATION