2001 TOYOTA PRIUS light

± DIAGNOSTICSNAVIGATION SYSTEM
DI±821
2001 PRIUS (RM778U) SYNC ± VG
(M6±8 ± M6±6)
Display ON
(Using an oscilloscope)0.5 V ± 1.3 V *1Screen is in disorder
TX1± (M6±10)AVC±LAN
communication circuit± Navigation system does not oper-
ate.
+B1 ± GND
(M7±1 ± M7±6)Constant10 ± 14 VNavigation system does not oper-
ate.
IG ± GND
(M7±2 ± M7±6)Ignition switch ON10 ± 14 VNavigation system does not oper-
ate.
DR ± GND
(M7±3 ± M7±6)Light control switch TAIL or HEAD
and cover the top of automatic
light control sensor9 V or moreNo problem is identified in the dis-
play.
ACC ± GND
(M7±4 ± M7±6)Ignition switch ACC10 ± 14 VNavigation system does not oper-
ate.
GND ± Body ground
(M7±6 ± Body ground)ConstantBelow 1 VAudio system is normal.
TAIL ± GND
(M7±8 ± M7±6)Light control switch TAIL or HEAD9 V or moreSwitching between Night and Day
mode cannot be done.

± DIAGNOSTICSNAVIGATION SYSTEM
DI±833
2001 PRIUS (RM778U)
6. Screen cannot be dimmed in night time.
INSPECTION PROCEDURE
1 Check if the screen is dimmed at night. (With the light control switch ON), do all
screens except the navigation screen appear in Night Mode?)
NG Check the light control switch.
OK
2 Check the multi display.
CHECK:
Check terminal TAIL.
OK:
TAIL: See ºMulti displayº of ºTERMINAL OF ECUº.
NG Replace or repair wire harness.
OK
3 Check the multi display.
PREPARATION:
Disconnect the multi display connector.
CHECK:
Check voltage terminals +B.
OK:
+B: 10 ± 14 V
CHECK:
Check voltage terminal ACC when turn ignition switch ACC or ON position.
OK:
ACC: 10 ± 14 V
CHECK:
Check continuity terminal GND.
OK:
GND: Continuity
NG Replace or repair wire harness.
DI7OZ±01

DI±846
± DIAGNOSTICSNAVIGATION SYSTEM
2001 PRIUS (RM778U)
15. Navigation screen cannot change to the night mode color.
INSPECTION PROCEDURE
1 Check the setting. (Is it set to Day Mode in screen adjustment?)
Yes Normal.
No
2 Check if the screen is dimmed at night. (With the light control switch ON, do all
screens except the navigation screen appear in Night Mode?)
NG Go to step 5.
OK
3 Does the beep sound by operating switches on the navigation screen?
OK Replace the navigation ECU.
NG
4 Check ºAVC±LAN communication circuitº (See page DI±860).
NG Replace or repair AVC±LAN circuit.
OK
Replace the navigation ECU.
DI7P8±01

I18151
Blower Switch
A/C Switch
I00339
Blinking Pattern
4 times
1 sec.
1 sec.
ON
OFF
ON
OFF
ON
OFF1 sec.
0.5 sec.
0.5
sec.1.5 sec 2.5 sec. 1.5 sec. No Malfunction
Malfunction Detected
u "
4.5 sec.
Repeat DI±872
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
3. INDICATOR CHECK
(a) Within 5 sec. after turning the ignition switch on, press the
A/C switch 3 times and turn the blower switch from OFF
to AUTO.
(b) Check that all the indicators light up and go off at 1 second
intervals 4 times in succession.
HINT:

After the indicator check is ended, the system enters the
DTC begins automatically.

Operate the blower switch from AUTO to except AUTO
position when desiring to cancel the check mode.
4. DTC CHECK (SENSOR CHECK)
(a) Perform an indicator check. After the indicator check is
completed, the system enters the DTC check mode auto-
matically.
(b) Read the DTC as indicated by the number of blinks of the
A/C indicator.
HINT:
The illustration shows the blinking pattern associated with the
DTC 12 and 23. If 2 or more DTCs (abnormalities) are indicated,
the lowest number (code) is output first.
(c) Identify the problem using the chart of the DTC.

± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±877
2001 PRIUS (RM778U) LOCk e SGLOCK
(A8±9 e A7±18)
W±L e BR±WStart engine. A/C compressor ON.Pulse generation
MGC e GNDLG RWBStart engine. A/C compressor: ONBelow 1.0MGC e GND
(A8±11 e A7±7)LG±R e W±BStart engine. A/C compressor: OFF10 ± 14
PSW e GND
(A8±11 e A7±7)L±Y e W±BA/C refrigerant pressure: less than 0.19 Mpa (2.0 kgf/cm2) or
more than 3.14 Mpa (3,140 kgf/cm2)
From 10 ± 14 to
Below 1.0
HTR2 e GND
(A8±13 e A7±7)
P e W±B
Start engine
Head lamp: OFF
Rear defogger: OFF
Set temp.: MAX. WARM
Blower mode dial: HI
Mode selector: F/D
Water temp.: 55 ± 70°C
Below 0.7
SGLOCK e GND
(A8±18 e A7±7)BR±W e W±BAlwaysContinuity
TE e SGTEWWIG ON. Ambient temp. 25°C (77°F)1.35 ± 1.75TE e SGTE
(A9±1 e A9±2)W e WIG ON. Ambient temp. 40°C (104°F)0.85 ± 1.25
SGTE e GND
(A9±2 e A7±7)W e W±BAlwaysContinuity
SGTR e GND
(A9±3 e A7±7)W e W±BAlwaysContinuity
TR e SGTRWWIG ON. Room temp. 25°C (77°F)1.8 ± 2.2TR e SGTR
(A9±4 e A9±3)W e WIG ON. Room temp. 40°C (104°F)1.2 ± 1.6
TS e S5TSWWIG ON. Solar sensor subject to electric light1.0 or moreTS e S5TS
(A9±5 e A9±6)W e WIG ON. Solar sensor cover by a clothBelow 1.0
S5TS e GND
(A9±6 e A7±7)W e W±BIG ON.4.5 ± 5.5
S5TPM e SGTPM
(A9±7 e A9±9)W e WIG ON.4.5 ± 5.5
TPM e SGTPMWWIG ON. Mode selector: FACEBelow 1.0TPM e SGTPM
(A9±8 e A9±9)W e WIG ON. Mode selector: DEF4.5 ± 5.5
SGTPM e GND
(A9±9 e A7±7)W e W±BAlwaysContinuity
AOF e GNDWWBIG ON. Mode selector: FACE10 ± 14AOF e GND
(A9±10 e A7±7)W e W±BIG ON. Mode selector: DEFBelow 1.0
AOD e GNDWWBIG ON. Mode selector: FACEBelow 1.0AOD e GND
(A9±11 e A7±7)W e W±BIG ON. Mode selector: DEF10 ± 14
AMH e GNDWWBIG ON. Set temp.: Max. COOL10 ± 14AMH e GND
(A9±13 e A7±7)W e W±BIG ON. Set temp.: Max. WARMBelow 1.0
AMC e GNDWWIG ON. Set temp.: Max. COOLBelow 1.0AMC e GND
(A9±14 e A7±7)W e WIG ON. Set temp.: Max. WARM10 ± 14
SGTP e GND
(A9±15 e A7±7)W e W±BAlwaysContinuity
TP e SGTPWWIG ON. Set temp.: Max. COOLBelow 1.0TP e SGTP
(A9±16 e A9±15)W e WIG ON. Set temp.: Max. WARM4.5 ± 5.5
S5TP e SGTP
(A9±17 e A9±15)W e WIG ON.4.5 ± 5.5
S5TPI e SGTPI
(A9±18 e A9±20)W e WIG ON.4.5 ± 5.5

I18163
ON
(±)TS
S5TS
(+)
DI±894
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals S5TS and TS of A/C amplifier connector.
PREPARATION:
(a) Remove center cluster module control with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals S5TS and TS of A/C ampli-
fier connector when the solar sensor is subjected to an electric
light, and when the sensor is covered by a cloth.
OK:
ConditionVoltage
Sensor subjected to electric lightBelow 4.0 V
Sensor covered by a cloth4.0 ± 4.5 V
HINT:
As the inspection light is gradually moved away from the sen-
sor, the voltage increases.
NG Go to step 2.
NG
Proceed to next circuit inspection shown on problem symptoms table (See page DI±874). Howev-
er, if DTC 21 is displayed, check and replace A/C amplifier.

I00325
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±895
2001 PRIUS (RM778U)
2 Check solar sensor.
PREPARATION:
Remove solar sensor (See page AC±59).
CHECK:
(a) Cover the sensor by a cloth.
(b) Measure resistance between terminals 1 and 2 of solar
sensor connector.
HINT:
Connect positive (+) lead of ohmmeter to terminal 2 and nega-
tive (±) lead to terminal 1 of the solar sensor.
OK:
Resistance : 8W (No continuity)
PREPARATION:
Remove the cloth from the solar sensor and subject the sensor
to electric light.
CHECK:
Measure resistance.
OK:
Resistance : Below 10 kW (Continuity)
HINT:
As the electric light is moved gradually away from the sensor,
the resistance increases.
NG Replace solar sensor.
OK
3 Check harness and connector between A/C amplifier and solar sensor
(See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.

I18158
ON
(+)
(±)IDH
I18398IDH ON
DI±940
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal IDH of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Turn ignition switch ON.
(b) Turn light control switch OFF.
(c) Turn rear defogger switch OFF.
(d) Measure voltage between terminal IDH of A/C amplifier.
OK:
Voltage: Below 1.0 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±874).
NG
2 Check voltage between terminal IDH of A/C amplifier and body ground.
PREPARATION:
Disconnect the connector from A/C amplifier.
CHECK:
(a) Turn ignition switch ON.
(b) Turn light control switch OFF.
(c) Turn rear defogger switch OFF.
(d) Measure voltage between terminal IDH of A/C amplifier
on wire harness side connector.
OK:
Voltage: Below 1.0 V
OK Check and replace A/C amplifier.
NG