2001 TOYOTA PRIUS check engine

I18006
1
I18156
ACT
DI±934
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
3 Check A/C magnetic clutch.
PREPARATION:
Disconnect magnetic clutch connector.
CHECK:
Connect positive (+) lead connected to battery to magnetic
clutch connector terminal 3 and negative (±) lead to body
ground.
OK:
Magnetic clutch is energized.
NG Repair A/C magnetic clutch.
OK
4 Check harness and connector between magnetic clutch relay and A/C amplifier,
A/C compressor and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown on
problem symptons table (See page DI±874).
5 Check voltage between terminal ACT of A/C amplifier connector side and body
ground.
PREPARATION:
(a) Disconnect A/C amplifier connector.
(b) Turn ignition switch ON.
CHECK:
Check voltage between terminal ACT of A/C amplifier harness
side connector.
OK:
Voltage : 10 ± 14 V
NG Check and replace engine ECU.
OK

I18157
ACT(±) (+)
ON
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±935
2001 PRIUS (RM778U)
6 Check voltage between terminal ACT of A/C amplifier connector and body
ground.
PREPARATION:
(a) Remove center cluster module control with connector still
connected.
(b) Start the engine and push AUTO switch.
CHECK:
Check the voltage between terminal ACT of A/C amplifier con-
nector and body ground when magnetic clutch is ON and OFF
by A/C switch.
OK:
Magnetic clutchVoltage
ON10 ± 14 V
OFFBelow 1.0 V
NG Check and replace A/C amplifier.
OK
7 Check harness and connector between magnetic clutch relay and A/C amplifier
(See page IN±41).
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown on
problem symptoms table (See page
DI±874).

I18171
(+) (±)WP ON
Z18060
15 2
3
123 5
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±937
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal WP of A/C amplifier and body ground.
PREPARATION:
(a) Remove the center cluster module control with connec-
tors still connected.
(b) Start engine.
(c) Operate blower motor.
CHECK:
Measure voltage between terminal WP of A/C amplifier and
body ground when each condition as shown in the chart.
OK:
conditionVoltage
Engine running10 ± 14 V
Engine stopBelow 1.0 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±874).
NG
2 Check A/C water pump relay.
PREPARATION:
Remove the A/C water pump relay from engine room R/B NO.
3.
CHECK:
Check continuity between each pair of terminals shown below
of magnetic clutch relay.
OK:
Tester connectionSpecified condition
1 ± 262.5 ± 90.9 W
3 ± 5No continuity
PREPARATION:
Apply battery positive (+) voltage between terminals 1 and 2.
CHECK:
Check continuity between terminals 3 and 5.
OK:
Continuity exists.
NG Replace magnetic clutch relay.
OK

I18174
ON
HTR2(+) (±)
DI±944
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check converter circuit (See page DI±934).
2 Check voltage between terminal HTR2 of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Start engine.
(b) Set temperature control switch on ºMAX. WARMº posi-
tion.
(c) Set blower switch on ºHIº position.
(d) Turn light control switch OFF.
(e) Turn defogger switch OFF.
(f) Check voltage between terminal HTR2 of A/C amplifier
and body ground at each conditions, as shown in the
chart.
OK:
ConditionVoltage

Air flow selector: FOOT

Water temp. : Below 65°C (149°F)Below 0.7 V

Air flow selector: FOOT/DEF

Water temp. : Below 60°C (140°F)Below 0.7 V

Air flow selector: DEF

Water temp. : 75°C (167°F)Below 0.7 V
OK Go to step 6.
NG

I18396
Engine Room R/B No. 3
HTR3 Fuse
Z18060
15 2
3
123 5
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±945
2001 PRIUS (RM778U)
3 Check HTR3 fuses.
PREPARATION:
Remove the HTR3 fuse from engine room R/B No. 3.
CHECK:
Check continuity of HTR1 and HTR2 fuses.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the HTR1 and HTR2 fuses
(See attached wiring diagram).
OK
4 Check HTR3 relays.
PREPARATION:
Remove the HTR3 relays from engine room relay block No. 3.
CHECK:
Check continuity between each pair of terminals shown below
of magnetic clutch relay.
OK:
Tester connectionSpecified condition
1 ± 262.5 ± 90.9 W
3 ± 5No continuity
PREPARATION:
Apply battery positive (+) voltage between terminals 1 and 2.
CHECK:
Check continuity between terminals 3 and 5.
OK:
Continuity exists.
NG Replace HTR3 relay.
OK

I18152
ON
HTR0
(+)
(±)
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±949
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check converter circuit (See page DI±934).
2 Check voltage between terminal HTR0, of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Start engine.
(b) Set temperature control switch on ºMAX WARMº position.
(c) Set blower switch on ºHIº position.
(d) Turn light control switch to OFF.
(e) Turn defogger switch OFF.
(f) Check voltage between terminal HTR0 of A/C amplifier
and body ground at each conditions, as shown in the
chart.
OK:
ConditionVoltage

Air flow selector: FOOT

Water temp. : Below 60°C (140°F)Below 0.7 V

Air flow selector: FOOT/DEF

Water temp. : Below 50°C (122°F)Below 0.7 V
OK Go to step 6.
NG

I18396
Engine Room R/B No. 3
HTR1 Fuse HTR2 Fuse
Z18060
15 2
3
123 5
DI±950
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
3 Check HTR1 and HTR2 fuses.
PREPARATION:
Remove the HTR1 and HTR2 fuses from engine room R/B NO.
3.
CHECK:
Check continuity of HTR1 and HTR2 fuses.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the HTR1 and HTR2 fuses
(See attached wiring diagram).
OK
4 Check HTR1 and HTR2 relays.
PREPARATION:
Remove the HTR1 and HTR2 relays from engine room relay
block NO. 3.
CHECK:
Check continuity between each pair of terminals shown below
of magnetic clutch relay.
OK:
Tester connectionSpecified condition
1 ± 262.5 ± 90.9 W
3 ± 5No continuity
PREPARATION:
Apply battery positive (+) voltage between terminals 1 and 2.
CHECK:
Check continuity between terminals 3 and 5.
OK:
Continuity exists.
NG Replace HTR1 and (or) HTR2 relay.
OK

I18160
ON
(+) (±)CF
RF
Terminal Condition Voltage
10 ± 14 V
Below 1.0 V
Below 1.0 V
10 ± 14 V Water temp.: Below 90°C (194 °F)
Refrigerant pressure:
Below 1,520 kPa (15.5 kgf/cm
2, 220 psi) RF e Body
ground
CF e Body
ground
Water temp.: Above 90°C (194 °F)
Refrigerant pressure:
Above 1,520 kPa (15.5 kgf/cm
2, 220 psi)
A/C switch: ON
A/C switch: OFF
DI±954
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals RF, CF of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Start engine.
(b) Turn A/C switch ON.
(c) Measure voltage between terminal RF, CF of A/C amplifi-
er and body ground at each conditions as shown in the
chart.
OK:
OK Go to step 4.
NG
2 Check Fan No. 1, No. 2 and No. 3 relays (See page AC±65).
NG Replace faulty relay
OK