AT
AT
AT
AT Air
Air
Air
Air Conditioner
Conditioner
Conditioner
Conditioner
- 176 -
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
A/C
A/C
A/C
A/C system
system
system
system performance
performance
performance
performance diagnosis
diagnosis
diagnosis
diagnosis
1. Air heater performance diagnosis .
Step Operation
Yes
No
1
W hether or not to conduct this diagnosis based on “ symptoms ” or
instruction of other diagnosis tables?
Go to Step 2. —
2
① Start the engine.
②
Let the engine idling.
Does the engine temperature reach normal operating temperature?
Go to Step 3. Go to Step 9.
3
①
Let the engine idling.
② Select “ FLOOR ” mode.
③
Set the minimum speed of blower.
④ Set the warmest temperature.
⑤
Sense the temperature of inlet and outlet hoses at the heater core.
Is the inlet hose of heater warmer than the outlet hose?
Go to Step 7. Go to Step 4.
4
①
Place the temperature gauge at the central air vent.
② Fix the temperature gauge onto the outlet hose at the heater core.
③
Set the maximum speed of blower.
④ Set the warmest temperature.
⑤
Record temperature at the position listed below:
C entral air vent on instrument panel .
O utlet hose at the heater core .
⑥ Compare the recorded temperatures.
Are these two temperatures nearly the same?
Go to Step 5. Go to Step 6.
5
① Check the following parts of vehicle for cold air leak and conduct
relevant maintenance:
F ront shield plate .
Internal circulation damper.
A ir heater, ventilation and A/C system module housing.
②
Conduct necessary maintenance.
Is the maintenance finished?
Go to Step 10. —
6
① Check the operation of temperature damper.
② Conduct necessary maintenance.
Is the maintenance finished?
Go to Step 10. —
7
① Shut down the engine.
②
Backflush the heater core.
③ Start the engine.
④
Select “ FLOOR ” mode.
⑤ Set the minimum speed of blower.
⑥
Set the warmest temperature.
⑦ Sense the temperature of inlet and outlet hoses at the heater core.
Is the inlet hose of heater warmer than the outlet hose?
Go to Step 8. Go to Step 10.
8
Replace the heater core.
Is the maintenance finished?
Go to Step 10. —
9
T roubleshoot too low engine temperature.
Is the maintenance finished?
Go to Step 10. —
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