Page 1223 of 1943
± DIAGNOSTICSCOMBINATION METER SYSTEM
DI±675
2001 PRIUS (RM778U) Trip meter cannot be reset.
1. ODO/TRIP switch
2. Combination meter ECU
Display cannot be shifted among ODO, TRIPA and TRIPB.1. ODO/TRIP switch
2. Combination meter ECU
Without resetting, the display returns to 0.0 km.1. ODO/TRIP switch
2. +B wire harness
3. Combination meter ECU
Error of accumulated distance is large.1. Accessory that utilizes vehicle speed signals.
2. GND wire harness
3. Brake ECU
4. Wire harness and connector
5. Combination meter ECU
Others:
SymptomSuspect area
Some indicators or warning lights are always ON.1. Meter circuit plate
2. Corresponding switch and ECU
3. Combination meter ECU
4. Multiplex communication circuit
Some indicators or warning lights do not light up.1. Bulb
2. Meter circuit plate
3. Corresponding switch and ECU
4. Combination meter ECU
5. Multiplex communication circuit
Buzzer does not stop.1. Combination meter ECU
2. Corresponding switch and ECU
Page 1761 of 1943

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±
Page 1764 of 1943

± 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±
±