Page 816 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-115
STEP 7. Check the wiring harness between defogger relay
connector C-201 (terminal 5) and the fusible link (1).
NOTE: Also check intermediate connector C-31 and junction
block connector C-216 for loose, corroded, or damaged termi-
nals, or terminals pushed back in the connector. If intermediate
connector C-31 and junction block connector C-216 is dam-
aged, repair or replace the connector as described in GROUP
00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201(terminal 5) and the fusible link (1) in good
condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. Check that the defogger
system works normally.
Page 817 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-116
STEP 8. Measure the voltage at defogger relay connector
C-201.
(1) Disconnect defogger relay connector C-201, and measure
the voltage at the junction block side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 1 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 10.
NO : Go to Step 9.
STEP 9. Check the wiring harness between defogger relay
connector C-201 (terminal 1) and ignition switch (IG2).
Page 818 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-117
NOTE: Also check junction block connector C-215 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-215 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 1) and ignition switch (IG2) in good
condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. Check that the defogger
system works normally.
STEP 10. Check A/C-ECU connector C-15 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connector C-15 in good condition?
YES : Go to Step 11.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.
Page 819 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-118
STEP 11. Check the wiring harness between defogger relay
connector C-201 (terminal 3) and A/C-ECU connector C-15
(terminal 8).
NOTE: Also check junction block connector C-211 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-211 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 3) and A/C-ECU connector C-15
(terminal 8) in good condition?
YES : Go to Step 12.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
Page 820 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-119
STEP 12. Check the wiring harness between defogger
relay connector C-201 (terminal 4) and choke coil
connector D-11 (terminal 1).
NOTE: Also check junction block connector C-204 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-204 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 4) and choke coil connector D-11
(terminal 1) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 13. Check choke coil connector D-11 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is choke coil connector D-11 in good condition?
YES : Go to Step 14.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.
Page 836 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-135
Temperature
setting23 Temperature setting
actualIgnition switch: ON The actual setting
corresponds with
diagnostic tool
display.
Vehicle speed 26 Actual vehicle speed Ignition switch: ON The vehicle speed
corresponds with
diagnostic tool
display.
A/C compressor
drive request27 Compressor clutch Engine: ON
Compressor:
ONDiagnostic tool
indication: "ON"
Compressor:
OFFDiagnostic tool
indication: "OFF"
Illumination 15 Display lighting Ignition switch: ON
Lights: ON
Diagnostic tool
indication: "ON"
Lights: OFF
Diagnostic tool
indication: "OFF"
Engine speed 23 Actual engine speed Engine: ON The engine speed
corresponds with
diagnostic tool
display.
In/out air select
switch state3 In/out air select
switch Ignition switch: ON In/out air
switch: ONDiagnostic tool
indication: "pressed"
In/out air
switch: OFFDiagnostic tool
indication: "release"
Rear defogger
relay72 Rear defogger relay Ignition switch: ON
Rear defogger:
ONDiagnostic tool
indication: "ON"
Rear defogger:
OFFDiagnostic tool
indication: "OFF" MUT-III
DIAGNOSTIC
TOOL DISPLAYITEM
NO.INSPECTION ITEM INSPECTION REQUIREMENT NORMAL VALUE
Page 838 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-137
CHECK AT A/C-ECU TERMINALM1552010300572
TERMINAL
NO.CHECK ITEM CHECKING REQUIREMENTS NORMAL CONDITION
1 Air mixing damper control motor When the air mix damper is
moved to the MAX. COOL
position. 10 V
When the air mix damper is
moved to the MAX. HOT
position. 0.5 V
2 Air mixing damper control motor When the air mix damper is
moved to the MAX. COOL
position. 0.5 V
When the air mix damper is
moved to the MAX. HOT
position. 10 V
3 Back-up power supply Always Battery positive voltage
4 Mode selection damper control
motor (DEF)When the damper is moved to
the FACE position. 0.5 V
When the damper is moved to
the DEF position. 10 V
5 Outside/inside air selection
damper control motor (outside)When the damper is moved to
the inside air recirculation
position.0.5 V
When the damper is moved to
the outside air induction
position.0 V (when the motor is
stopped)
6 Outside/inside air selection
damper control motor (inside)When the damper is moved to
the inside air recirculation
position.0 V (when the motor is
stopped)
When the damper is moved to
the outside air induction
position.0.5 V
8 Rear defogger relay Ignition switch: ON Battery positive voltage
9 Front blower relay Ignition switch: ON Battery positive voltage
10 A/C compressor relay A/C compressor relay: ON Battery positive voltage
11 Mode selection damper control
motor (FACE)When the damper is moved to
the FACE position. 10 V
When the damper is moved to
the DEF position. 0.5 V
12 A/C pressure sensor Ignition switch: ON 5 V
Page 849 of 1500

ON-VEHICLE SERVICE
HEATER, AIR CONDITIONING AND VENTILATION55-148
POWER RELAY CHECKM1552008800321
BLOWER RELAY CONTINUITY CHECK
Hissing or swishing
noiseLow refrigerant quantity Refrigerant level Check system for leaks
and charge to
specification
Rattling (Internal
compressor)Lack of lubricating oil. In a
system with a gas leak
the oil has escaped with
the refrigerantRattling noise from
internal compressorRepalce the compressor
and also fix the system
leak to prevent
reoccurrance
Wooing (Resonant
noise)Drive accessory (P/S
pump, Alternator,etc)
resonating at specific
engine speedThe drive accessories for
vibrationStop vibrations of the
assembly or modify
transmission route to the
vehicle body
Cooing (Discharge
pulsation noise)Pressure fluctuation of
refrigerant discharged
from compressor, which
vibrates the high pressure
pipingRemove the piping
mounting clamps and
re-check. Hold the
condenser without
mountings by hand and
re-checkPut rubber bush between
pipe clamps and the
vehicle body. decrease
refrigerant to minimum
specified level. NOISE DESCRIPTION POSSIBLE CAUSE CHECK REPAIR
BATTERY
VOLTAGETESTER
CONNECTIONSPECIFIED
CONDITION
Not applied 4
5 Open circuit
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 3 to the
negative battery
terminal4
5 Less than 2 ohms