2001 TOYOTA PRIUS fuse

DI±494
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
DTCAlways ONMalfunction in EMPS ECU
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
Always ONThere is a malfunction in the EMPS ECU internal circuit.

Power source circuit

EMPS ECU

PS warning light circuit
INSPECTION PROCEDURE
1 Is DTC output?
Check DTC on page DI±460.
YES Repair circuit indicated by output code.
NO
2 Is normal code displayed?
YES Check and replace EMPS ECU.
NO
3 Does PS warning light goes off?
YES Check for open or short circuit in harness and
connector between ECU±IG fuse and EMPS
ECU (See page IN±41).
NO
DI7RD±01

N14677
Fuse
AB0119H01300
H01301
Airbag Sensor Assembly
ON
LA
(+)
(±)
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±639
2001 PRIUS (RM778U)
Does not light up, when ignition switch is turned to ON
1 Check AM2 Fuse.
PREPARATION:
Remove the AM2 fuse.
CHECK:
Check continuity of the AM2 fuse.
OK:
Continuity
HINT:

Fuse may be burnt out even if it appears to be OK during
visual inspection.

If fuse is OK, install it.
NG Go to step 4.
OK
2 Prepare for inspection (See step 1 on page DI±629).
3 Check SRS warning light circuit.
PREPARATION:
(a) Disconnect the airbag sensor assembly connector.
(b) Connect negative (±) terminal cable to the battery.
(c) Turn the ignition switch to ON.
CHECK:
Measure the voltage between body ground and LA terminal of
the harness side connector of the airbag sensor assembly.
OK:
Voltage: 10 ± 14 V
NG Check combination meter or repair SRS warn-
ing light circuit.
OK
Replace airbag sensor assembly.

DI±640
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
4 Is new AM2 fuse burnt out again?
NO Using simulation method, reproduce malfunc-
tion symptoms (See page IN±30).
YES
Check harness between AM2 fuse and SRS
warning light.

DI±654
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT INSPECTION
DTC P1520 Stop light switch circuit
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the hybrid vehicle control ECU.
When the hybrid vehicle control ECU receives this signal, it cancels the cruise control.
A fail±safe function is provided so that the cancel functions normally, even if there is a malfunction in the stop
light signal circuit.
The cancel condition is that battery voltage is supplied to terminal STP.
When the brake is on, battery voltage is normally applied through the STOP fuse and stop light switch to
terminal STP of the hybrid vehicle control ECU, and the hybrid vehicle control ECU turns the cruise control
OFF.
If the harness connected to terminal STP has an open circuit, terminal STP will have battery voltage and
the cruise control will be turned OFF.
DTC No.Detection ItemTrouble Area
P1520Stop light switch circuit.

Stop light switch

Harness or connector between hybrid vehicle control ECU
and stop light switch circuit

Hybrid vehicle control ECU
DI7NI±01

± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±659
2001 PRIUS (RM778U)
Power source circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the hybrid vehicle control ECU.
WIRING DIAGRAM
See page DI±156.
INSPECTION PROCEDURE
1 Check IGN and EFI fuse.
CHECK:
Check continuity of IGN and EFI fuse.
OK:
Continuity
NG Replace the failure fuse.
OK
2 Check voltage between terminals IGSW, BATT and GND of hybrid vehicle control
ECU connector (See page IN±41).
PREPARATION:
(a) Turn ignition switch OFF.
(b) Disconnect the hybrid vehicle control ECU connector.
CHECK:
Measure voltage between terminals IGSW, BATT and GND
OK:
Voltage: 10 ± 14 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±648).
NG
DI7NJ±01

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.

DI7XS±01
DI±674
± DIAGNOSTICSCOMBINATION METER SYSTEM
2001 PRIUS (RM778U)
PROBLEM SYMPTOMS TABLE
TROUBLESHOOTING:
Flow chart No.SymptomSee page
1Check the communication between the combination meter and the multiplex com-
munication circuit.DI±671
2The whole meter does not functionDI±672
3The margin of error in speedometer is large. Or it remains as 0 mph.DI±673
4Fuel receiver gauge is inoperative or improper.DI±674
5Indicators or warning lights do not light up.DI±676
Fuel gauge:
SymptomSuspect AreaSee page
Displayed level is higher or lower than the actual level.1. Inclination sensor resetting
2. Body ECUBE±47
IN±41
General:
SymptomSuspect area
Meter display does not properly function.3. Combination meter ECU
Entirely black screen appears.1. Fuse
2. Wire harness and connector
3. Combination meter ECU
Turning the light control switch ON does not dim the light.1. Illumination switch
2. Wire harness and connector
3. Combination meter ECU
Brightness cannot be changed by the illumination switch operation.1. Illumination switch
2. Wire harness and connector
3. Combination meter ECU
Speedometer:
SymptomSuspect area
Improper display (Remained as 0 km/h)1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
Speedometer only does not light up.1. Combination meter ECU
Abnormal display (Incomplete numbers displayed)1. Combination meter ECU
DIsplayed value changes frequently or sharply.1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
Margin of error in speedometer is large.1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
ODO/TRIP Meter:
SymptomSuspect area
ODO/TRIP only does not light up.1. Combination meter ECU
Abnormal display (Incomplete number displayed)1. Combination meter ECU
Both meters do not integrate values. (When speedometer is normal)1. Combination meter ECU
Trip meter only does not integrate values.1. ODO/TRIP switch
2. Combination meter ECU

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±691
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check ECU±B, DC/DC, GAUGE and DOOR fuse.
CHECK:
Check continuity of ECU±B, DC/DC, GAUGE and DOOR fuse.
OK:
Continuity
NG Replace the failure fuse.
OK
2 Check voltage between terminals B, BDR and E of body ECU connector.
PREPARATION:
(a) Turn ignition switch OFF.
(b) Disconnect the Body ECU connector.
CHECK:
Measure voltage between terminals B, BDR and E.
OK:
Voltage: 10 ± 14V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±683).
NG
3 Check wireharness and connector between body ECU and body ground (See
page IN±41).
NG Repair or replace wireharness or connector.
OK
Check and repair wireharness and connector
between Body ECU and battery.