Page 1313 of 2234
55±18
±
HEATER & AIR CONDITIONER COMBUSTION TYPE POWER HEATER SYSTEM
AVENSIS REPAIR MANUAL (RM1018E) DTC No.
Comment / Remedy
Description of fault
071Surface sensor break
Check connecting leads.
Resistance value between 4 and 11 at connector B > 2 (If
break)
072Surface sensor short±circuit
Check connecting leads.
Resistance value between 4 and 11 at connector B > 50 (If
short±circuit)
090
092
093Control unit detective (Internal fault / Reset)
Control unit detective (ROM error)
Control unit detective (RAM error)
Control unit malfunction due to interference voltage from ve-
hicle electrical system;
possible causes low batteries, chargers, other sources of
interference; eliminate interference voltages.
Internal faults detected in microprocessor / memory detected.
Replace control unit.
097Internal control unit faultsOther faults which cannot lead to DTC No. 90, 92 and 93,
replace control unit.
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Page 1314 of 2234
550ZH±01
I32392
3
4
I32393
5
6
I12755
9
12
Ohmmeter
±
HEATER & AIR CONDITIONER COMBUSTION TYPE POWER HEATER SYSTEM
55±19
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION
1. INSPECT HEATER ASSY
(a) Inspect the water temperature sensor.
(1) Using an ohmmeter, measure the resistance be-tween the terminals 3 and 4 of heater wire.
Resistance: Refer to the graph
If the resistance is not as specified, replace the heater wire.
(b) Inspect the overheat sensor.
(1) Using an ohmmeter, measure the resistance be-tween the terminals 5 and 6 of heater wire.
Resistance: Refer to the graph
If the resistance is not as specified, replace the heater wire.
(c) Inspect the glow plug.
(1) Using an ohmmeter, check the continuity by mea-sure the resistance between terminals 9 and 12 of
heater wire.
Standard resistance: about 0.5 (20 C, reference
value)
If the resistance is over 1 , replace the heater wire.
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Page 1315 of 2234

I32394
12
I32395
Wire harness side:
55±20
±
HEATER & AIR CONDITIONER COMBUSTION TYPE POWER HEATER SYSTEM
AVENSIS REPAIR MANUAL (RM1018E)
(d) Inspect the flame sensor. (1) Using an ohmmeter, measure the resistance be-tween terminals 1 and 2 of heater wire.
Resistance: Refer to the graph
If the resistance is not as specified, replace the heater wire.
2. INSPECT HETER SWITCH ASSY
(a) Disconnect the connector from the power heater switch and inspect the connector on the wire harness side, as
shown in the chart.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
4 ± GroundConstantContinuity
3 ± GroundTurn ignition switch ONBattery voltage
3 ± GroundTurn ignition switch OFFNo voltage
1 ± GroundTurn light control switch TAIL or HEADBattery voltage
1 ± GroundTurn light control switch OFFNo voltage
If the circuit is as specified, replace the power heat-
er switch.
If the circuit is not as specified, inspect the circuits
connected to other parts.
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Page 1316 of 2234
I32396
From back side:
±
HEATER & AIR CONDITIONER COMBUSTION TYPE POWER HEATER SYSTEM
55±21
AVENSIS REPAIR MANUAL (RM1018E)
(b) Connect the connector to the power heater switch and in-
spect the connector from the back side, as shown in the
chart.
Tester connectionConditionSpecified condition
6 ± GroundTurn the ignition switch ON and power heater
switch ONBattery voltage
6 ± GroundTurn the ignition switch ON and power heater
switch OFFNo voltage
If the circuit is not as specified, replace the power
heater switch.
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Page 1317 of 2234
550ZE±01
±
HEATER & AIR CONDITIONER ELECTRICAL TYPE POWER HEATER SYSTEM
55±13
AVENSIS REPAIR MANUAL (RM1018E)
ELECTRICAL TYPE POWER HEATER SYSTEM
PROBLEM SYMPTOMS TABLE
Use the table below to help you find the cause of the problem. The numbers \
indicate the priority of the likely
cause of the problem. Check each part in order. If necessary, replace these parts.
SymptomSuspect AreaSee page
PTC heater does not operate, when perform in these conditions:
Engine coolant temp.: 70 C (158 F) or below
Engine speed: 650 rpm or above
Temperature control selector: MAX. HOT
Ambient temperature: Below 10 C (50 F)
1. HTR1 Fuse
2. HTR2 Fuse
3. HTR1 relay
4. HTR2 relay
5. PTC heater
6. ECM
7. Wire harness±
±
±
±
55±14
±
±
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Page 1318 of 2234
550ZF±01
I32391
55±14
±
HEATER & AIR CONDITIONER ELECTRICAL TYPE POWER HEATER SYSTEM
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION
1. INSPECT HEATER ASSY
(a) Check continuity. (1) Using an ohmmeter, check for continuity betweeneach terminal of connector and earth wire.
If no continuity, replace the heater radiator.
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Page 1319 of 2234
550ZE±01
±
HEATER & AIR CONDITIONER ELECTRICAL TYPE POWER HEATER SYSTEM
55±13
AVENSIS REPAIR MANUAL (RM1018E)
ELECTRICAL TYPE POWER HEATER SYSTEM
PROBLEM SYMPTOMS TABLE
Use the table below to help you find the cause of the problem. The numbers \
indicate the priority of the likely
cause of the problem. Check each part in order. If necessary, replace these parts.
SymptomSuspect AreaSee page
PTC heater does not operate, when perform in these conditions:
Engine coolant temp.: 70 C (158 F) or below
Engine speed: 650 rpm or above
Temperature control selector: MAX. HOT
Ambient temperature: Below 10 C (50 F)
1. HTR1 Fuse
2. HTR2 Fuse
3. HTR1 relay
4. HTR2 relay
5. PTC heater
6. ECM
7. Wire harness±
±
±
±
55±14
±
±
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Page 1320 of 2234
550ZF±01
I32391
55±14
±
HEATER & AIR CONDITIONER ELECTRICAL TYPE POWER HEATER SYSTEM
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION
1. INSPECT HEATER ASSY
(a) Check continuity. (1) Using an ohmmeter, check for continuity betweeneach terminal of connector and earth wire.
If no continuity, replace the heater radiator.
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