18 · Diagnostics

L12 Climate control unit cools too much

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2002
Section: Climate control › L12 Climate control unit cools too much

‹ Prev L10 Climate control unit does not cool Next › L15 Climate control unit does not heat

Fault diagnosisL12 Climate control unit cools too much

L12 Climate control unit cools too much

The control button operates the passenger compartment air fan normally, but the temperature of the air is not as required.

Step	Test procedure	Result	Action
1	CHECKING AIR TEMPERATURE Check the temperature of the air at the vents (See Test 5040A Data not yet available )	OK	Move onto step 8
		Ambient temperature at the vents	Move onto step 2
		Temperature at the vents higher than desired	Move onto step 3
2	CHECKING SYSTEM PRESSURE Connect the climate control system to the recharging equipment and check the system pressures (See Test 5040B Data not yet available ).	OK	Move onto step 8
		High and low pressure values below correct figures.	Recharge the system Op. 5040A10 End of diagnosis
		High and low pressure values above correct figures.	Move onto step 3
		Low pressure value correct, but high pressure value above correct level (rapid compressor cycles as engine rpm rises)	Move onto step 4
		Low pressure value high and high pressure value below correct levels	Replace the compressor Op. 5040A20 End of diagnosis
		High and low pressure vaules do not alter when the air conditioning is activated.	Replace the compressor Op. 5040A20 End of diagnosis
3	CHECKING CONDENSER FAN Check that the fan cools the condenser correctly.	OK	Move onto step 4
3		Electric fan defective	Replace the fan Op. 5040C30 End of diagnosis
4	CHECKING CIRCUIT CHARGE Check that the system charge is not excessive.	OK	Move onto step 5
4		Excessive system charge	Restore the correct charge Op. 5040A10 End of diagnosis
5	CHECKING COOLANT CIRCUIT OBSTRUCTIONS Check that the pipes and the filter are not obstructed.	OK	Move onto step 6
		Pipe from compressor to condenser obstructed	Replace the pipe Op. 5040A50 End of diagnosis
		Pipe from condenser to filter obstructed	Replace the pipe Op. 5040A52 End of diagnosis
		Pipe from filter to expansion valve obstructed	Replace the pipe Op. 5040A54 End of diagnosis
		Filter obstructed	Replace the pipe Op. 5040A44 End of diagnosis
6	CONDENSER CHECK Check that the condenser is not blocked.	OK	Move onto step 7
6		Condenser blocked	Replace the condenser Op. 5040A40 End of diagnosis
7	EXPANSION VALVE CHECK Check the operation of the expansion valve.	OK	Move onto step 8
7		Expansion valve defective	Replace the expansion valve Op. 5040B30 End of diagnosis
8	CHECKING CORRECT OPERATION Check that the fault is no longer present	OK	Incorrect selection of diagnostic procedure
8		Fault persists	Incorrect selection of diagnostic procedure

‹ Prev L10 Climate control unit does not cool Next › L15 Climate control unit does not heat

Parts & tools for this job For 2000 Alfa Romeo 147

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