|  |  | Results of the tests | 
| 0 | PRELIMINARY CHECKS | All OK | Problems met | Operation | 
|---|
|  | First
check that the unpleasant smells are not coming from the outside:
they can be eliminated straight away by switching on the recirculation function | Continue to Step 
                              1 | Recirculation not working | See table 
                                 L16 | 
| 1 | CONDENSATION DRAINAGE PIPE CHECK | All OK | Problems met | Operation | 
|---|
|  | Check
the state of the condensation drainage pipe from the air conditioning
unitIt should not be obstructed or dirty | Continue to Step 
                              2 | Pipe obstructed | Renew the drainage pipe
(see Assembly 5040C) | 
| 2 | CHECKING POLLEN FILTER | All OK | Problems met | Operation | 
|---|
|  | Check
the condition of the pollen filter |  | It should be remembered that the
pollen filter should be replaced about once a year. | 
 | Continue to Step 
                              3 | Filter obstructed | Replace the pollen filter 
                               Op.   5010B09 | 
| 3 | AIR SUPPLY DUCTS CHECK | All OK | Problems met | Operation | 
|---|
|  | Check
the air supply ducts: they should not be obstructed with dirt or
foul smelling substances | Continue to Step 
                              4 | Vents malfunction | Wash the ducts (after removing
the electric fan)Restore the ducts (see Assembly 5010B) | 
| 4 | CHECKING HEATER RADIATOR | All OK | Problems met | Operation | 
|---|
|  | Check
the heater radiator: the external fins should not be obstructed
with dirt or other substances | Continue to Step 
                              5 | Radiator dirty or obstructed | Clean the radiator or replace
it 
                               Op.   5040C50 | 
| 5 | HECK ON CORRECT OPERATION | All OK | Problems met | Operation | 
|---|
|  | Check
that the fault is no longer present | End of diagnosis | Fault persists | Search for the
fault starting from another symptom' |