L12 CLIMATE CONTROL TOO COLD - Alfa - 156 - eLearn

3233110 - L12 CLIMATE CONTROL TOO COLD

The control unit regularly operates the fan which sends air to the passenger compartment in accordance with the pre-set flows, but this air lowers the high temperature in the passenger compartment too muchThis fault may be accompanied by a sudden increase in the temperature of the air sent to the passenger compartmentThis is due to the operation of the system which switches off the cooling circuit if the temperature at the evaporator decreases too much.

1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
1.6 TS 1.8 TS [d] 2.5 V6 1.9 JTD 8v	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket.Check that there are no faults in the climate control control unit. Check, in particular, that the control unit is correctly set considering there is no frost sensor	Continue to Step 2	Error detected in the control unit	Proceed according to the diagnostic equipment instructions
1.6 TS 1.8 TS [d] 2.5 V6 1.9 JTD 8v		Continue to Step 2	Failed dialogue with the control unit	Restore: connection between the climate control unit and the diagnostic connector supply for the climate control unit ( See E6020 AIR CONDITIONING ).
2.4 JTD 10v	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket.Check that there are no faults in the climate control unit.Check, in particular, that the control unit is correctly set to take into account whether or not there is a frost sensor:	Continue to Step 2	Error detected in the control unit	Proceed according to the diagnostic equipment instructions
2.4 JTD 10v		Continue to Step 2	Failed dialogue with the control unit	Restore: connection between climate control unit and diagnostic connector supply for the climate control unit ( See E6020 AIR CONDITIONING ).
2	MIXING MOTOR CHECK	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the mixing motor	Continue to Step 3	Faulty mixing motor connection	Restore the connection between the control unit and the mixing motor Failed dialogue with the control unit See E6020 AIR CONDITIONING Restore:
		Continue to Step 3	connection between climate control unit and diagnostic connector	Replace the mixing motor Op. 5040D77
3	FOUR STAGE PRESSURE SWITCH CHECK	All OK	Problems met	Operation
	Check the four stage pressure switch See Test 5040BA Check operation of four stage pressure switch	Continue to Step 4	Pressure switch defective	Replace the pressure switch Op. 5040B14
		Continue to Step 4	Connections not correct	Restore the connections with the engine management control unit See E6021 COMPRESSOR ENGAGEMENT
4	SYSTEM PRESSURE CHECK	All OK	Problems met	Operation
	Check the system pressure: TESTS See Test 5040B Check on operation of air conditioning system (pressures)	Continue to Step 5	High pressure does not increase or low pressure decreases too much: insufficient fluidHigh pressure continus to increase: too much fluid	Proceed with re-pressurizign the system: Op. 5040A10
5	CORRECT OPERATION CHECK	All OK	Problems met	Operation
	Check that fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'