2002 ISUZU AXIOM air conditioning

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±91
Troubleshooting With Self-Diagnosis Function
Overview of Self-Diagnosis Function
Sensors (input) and actuators (output) are used to check
circuit function and provide essential data on these
circuits. For more detailed information, refer to the
[Inspection and Repair] Sections for the applicable
system or component.
The Table below shows how to turn the self-diagnosis
function on and off.
Self-Diagnosis Operation Procedure
865R200033

1A±92
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
StepActionValue(s)Ye sNo
11. Allow the engine to idle until it completely warms up.
2. Turn the starter switch to the OFF position.
3. Place a 60±watt lamp approximately 15 cm from the
sun sensor.
NOTE: This procedure is best performed at night or in
a dark, unlit area.
Is the action complete?
ÐGo to Step 2Ð
2Simultaneously press and hold the RESET key and the
CLOCK key (display unit).
Move the starter switch to start the engine.
Does DIAG appear on the display?
ÐGo to Step 3
Replace
display unit
3Press the COMPUTER MODE key.
Does DIAG AIRCON appear on the display?
ÐGo to Step 4
Replace
audio unit
4NOTE: A '1' should appear in the set temperature
segment of the display.
Does '0' appear in the outside air segment of the
display?
ÐGo to Step 6Go to Step 5
5Repair or replace damaged parts.
NOTE: Refer to
Step 1 Trouble Code Table.
Is the action complete?ÐGo to Step 1Ð
6Press and release the  fan switch (one time only).
NOTE: A '2' should appear in the set temperature
segment of the display.
Does '0' appear in the outside air segment of the
display?
ÐGo to Step 8Go to Step 7
7Repair or replace damaged parts.
NOTE: Refer to
Step 2 Trouble Code Table.
Is the action complete?ÐGo to Step 1Ð
8Press and release the  fan switch (one time only).
NOTE:

Refer to
Step 3 Sensor Output Check for a sample
output value.

A '3' should appear in the set temperature
segment of the display.
Does the correct sensor output value appear in the
outside air segment of the display?
ÐGo to Step 10Go to Step 9
9Repair or replace damaged parts.
NOTE: Refer to
Trouble Spot Inspection.
Is the action complete?ÐGo to Step 1Ð
10Press and release the  fan switch one time only.
NOTE: Refer to
Step 4 (Operation Check) for display
readings and inspection steps.
Are all parts operating normally?
ÐGo to Step 12Go to Step 11

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±93
StepNo Ye s Value(s) Action
11Repair or replace damaged parts.
NOTE: Refer to
Trouble Spot Inspection.
Is the action complete?ÐGo to Step 1Ð
121. Press and release the
fan switch (one time only).
2. Press the DEF switch several times.
NOTE: A '3' should appear in the set temperature
segment of the display.
Does the correct sequence pattern (1, 2, 1, 2) appear in
the outside air segment of the display?
ÐGo to Step 15Go to Step 13
13Perform diagnosis for DEF switch, intake actuator, and
AUTO A/C control unit.
Have the diagnosis procedures been completed.
ÐGo to Step 14Ð
141. Press and release the
fan switch (one time only).
2. Press the DEF switch several times.
Are all parts operating normally?
ÐGo to Step 15
Replace
display unit
15Turn the starter switch OFF.
Is the action complete?
ÐÐÐ

1A±94
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
STEP 1: Trouble Code Table
Trouble
CodeDefective PartTrouble
CodeDefective Part
1In Car Sensor Open Circuit± 1In Car Sensor Short Circuit
2Ambient Sensor Open Circuit± 2Ambient Sensor Short Circuit
3Sun Sensor Open Circuit± 3Sun Sensor Short Circuit
4Duct Sensor Open Circuit± 4Duct Sensor Short Circuit
5Mix Potentiometer Open Circuit± 5Mix Potentiometer Short Circuit
6Mode Encoder Open Circuit
7Intake Encoder Open Circuit
0No Defective Part
STEP 2: Trouble Code Table
Trouble
CodeDefective PartTrouble
CodeDefective Part
1In Car Sensor Open Circuit± 1In Car Sensor Short Circuit
2Ambient Sensor Open Circuit± 2Ambient Sensor Short Circuit
3Not Used± 3Sun Sensor Short Circuit
4Duct Sensor Open Circuit± 4Duct Sensor Short Circuit
5Mix Potentiometer Open Circuit± 5Mix Potentiometer Short Circuit
6Mode Encoder Open Circuit
7Intake Encoder Open Circuit
0No Defective Part

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±95
STEP 3: Sensor Output Check
865R200035

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HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
STEP 4: Operation Check
865R200032

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±97
Inspection By Failed Location
Inspection of the Sensors
When the self-diagnosis function has determined that
trouble is present on the sensors, check them according
to the following flow chart.
F01RY00005

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HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Chart 1: In Car Sensor
D08R200029
StepActionValue(s)Ye sNo
1Disconnect the in car sensor connector. (No.I-17)
Is performance of the sensor normal? (Refer to the
later section on ªIndividual Inspectionº)ÐGo to Step 2
Replace the
in car sensor
2Is there continuity between the harness side connector
No.I20±1 and No.I17±3?
ÐGo to Step 4Go to Step 3
3Repair an open circuit between terminal No.I20±1 and
No.I17±3.
Is the action complete?
ÐGo to Step 2Ð
4Is there continuity between the harness side connector
No.I20±11 and No.I17±4?
ÐGo to Step 6Go to Step 5
5Repair an open circuit between terminal No.I20±11 and
No.I17±4.
Is the action complete?
ÐGo to Step 4Ð
6Replace the auto air conditioner control unit.
Is the action complete?
ÐVerify repairÐ