warning lights TOYOTA PRIUS 2001 Service Owner's Manual

± DIAGNOSTICSCOMBINATION METER SYSTEM
DI±681
2001 PRIUS (RM778U)
5. Indicators or warning lights do not light up. (*multiplex communication circuit input
indicator or warning)
INSPECTION PROCEDURE
1 Multiplex communication circuit input indicator or warning.
2 Communication check.
CHECK:
Check if the communication between the combination meter and the multiplex communication circuit is nor-
mal or not.
Ye s
No Communication error. Wire harness faulty.
3 Check the bulb or circuit plate.
CHECK:
Check if the bulb circuit plate is normal or not. Check open or short circuit in wire harness.
Ye s
No Bulb or circuit plate faulty.
DI7XX±01

± BRAKETROUBLESHOOTING
BR±3
1518 Author: Date:
2001 PRIUS (RM778U) Noise from brakes
1. Pad or lining (Cracked or distorted)
2. Installation bolt (Loose)
3. Disc or drum (Scored)
4. Pad support plate (Loose)
5. Sliding pin (Worn)
6. Pad or lining (Dirty)
7. Pad or lining (Glazed)
8. Tension or return spring (Faulty)
9. Anti±squeal shim (Damaged)
10.Shoe hold±down spring (Damaged)BR±23
BR±32
BR±26
BR±26
BR±32
BR±23
BR±26
BR±23
BR±32
BR±23
BR±32
BR±32
BR±23
BR±32
Brake warning light lights up*1
(Parking brake pedal released)
1. Brake fluid level
2. Hydraulic brake booster power supply system (Faulty)
BR±41
Brake warning light lights up and brake warning buzzer sounds*2Hydraulic brake booster power supply system (Faulty)BR±41
ABS warning light lights up*31. Anti±lock brake system (Faulty)
2. Hydraulic brake booster power supply system (Faulty)
BR±41
*1, *3: The light may stay on for about 60 seconds after the engine has been started. It is normal if it goes
out after a while.
*
2, *3: Depressing the brake pedal repeatedly may turn on the warning light and buzzer. It is normal if the
light goes out and the buzzer stops sounding after a few seconds.

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

I17865
Fuel Sender Gauge Connector
I17865
Fuel Sender Gauge Connector
I01277
BatteryWarning Light Ignition
Switch
Wire Harness Side
1
I01278
BE±44
± BODY ELECTRICALCOMBINATION METER
2001 PRIUS (RM778U)
5. INSPECT FUEL SENDER GAUGE VOLTAGE
Measure the voltage between terminals 1 and 6 for each fuel
level.
HINT:
The fuel sender gauge cannot be removed.
As the resistance value changes according to the remaining
fuel amount, refer to the above standard value.
Fuel levelResistance (W)
FullApprox. 430
HalfApprox. 1000 ± 2000
EmptyApprox. 5000
If resistance value is not as specified, replace the fuel tank.
If resistance value is as specified, replace the combination me-
ter.
6. INSPECT TEMPERATURE SENDER RESISTANCE
Measure the resistance between terminal 4 and 8
If the resistance value is not in the following area, replace fuel
tank.
1.5 ± 100 (W) at 0 ± 30°C
7. INSPECT LOW OIL PRESSURE WARNING LIGHT
(a) Disconnect the connector from the warning switch and
ground terminal of the wire harness side connector.
(b) Turn the ignition switch ON, check that the warning light
lights up.
If the warning light does not light up, test the bulb or inspect wire
harness.
8. INSPECT LOW OIL PRESSURE SWITCH CONTINUITY
(a) Check that continuity exists between terminal and ground
with the engine stopped.
(b) Check that no continuity exists between terminal and
ground with the engine running.
HINT:
Oil pressure should be over 24.5 kPa (0.25 kgf/cm
2, 3.55 psi)
If operation is not as specified, replace the switch.

BE1217
BatteryWarning Light
Ignition
Switch
I11650
BE0044
BatteryWarning Light
Ignition
Switch
Z11183
± BODY ELECTRICALCOMBINATION METER
BE±45
2001 PRIUS (RM778U)
9. INSPECT BRAKE WARNING SYSTEM LIGHT
(a) Disconnect the connector from the brake fluid warning
switch.
(b) Connect terminals of the wire harness side of the level
warning switch connector.
(c) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or wire har-
ness.
10. INSPECT BRAKE FLUID LEVEL WARNING SWITCH
CONTINUITY
(a) Remove the reservoir tank cap and strainer.
(b) Disconnect the connector.
(c) Check that no continuity exists between terminals with the
switch OFF (float up).
(d) Use syphon, etc. to take fluid out of the reservoir tank.
(e) Check that continuity exists between terminals with the
switch ON (float down).
(f) Pour the fluid back in the reservoir tank.
If operation is not as specified, replace the switch.
11. INSPECT PARKING BRAKE WARNING LIGHT
(a) Disconnect the connector from the parking brake switch.
(b) Ground terminal of the wire harness side connector.
(c) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or inspect wire
harness.
12. INSPECT PARKING BRAKE SWITCH CONTINUITY
(a) Check that continuity exists between terminal and switch
body with the switch ON (switch pin released).
(b) Check that no continuity exists between terminal and
switch body with the switch OFF (switch pin pushed in).
If operation is not as specified, replace the switch or inspect
ground point.

BE0044
BatteryWarning Light
Ignition
Switch BE±46
± BODY ELECTRICALCOMBINATION METER
2001 PRIUS (RM778U)
13. INSPECT OPEN DOOR WARNING LIGHT
Disconnect the connector from the door courtesy switch, and
ground terminal 1 of the wire harness side connector and check
that the warning light lights up.
If the warning light does not light up, inspect the bulb or wire har-
ness.