| 0 | PRELIMINARY CHECKS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| Connect the climate control system to the special repressurizing equipment and check the system pressures by carrying out the See Test 5040OB Air conditioning system operational check (pressure)Check the wear condition and correct belt alignment and tensioning.Run the engine at idle speed with the A/C system off and check whether the noise comes from other auxiliary components (engine fan, water pump, alternator). Increase the rpm and check for vibrations. | Move on to Step 2 | 1. Pressure level incorrect | 1. Move on to Step 1 |
| 2. Belt alignment/tension incorrect or belt worn. | 2. Restore correct alignment/tension or replace the belt. |
| 3. The noise is from other auxiliary components (engine cooling fan, coolant pump, alternator). | 3. Continue as indicated in the diagnostic test procedure. |
| 1 | CHECK PRESSURE VALUES IN HIGH AND LOW PRESSURE CIRCUIT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| Keep the recharging device connected and check the pressure levels in the system high and low pressure circuit with the compressor on and engine running:- pressure values low in high and low pressure circuit;
- pressure values high in high and low pressure circuit;
- check that the pressure values (high and low) during compressor operation do not pulse and that the circuit does not equalise slowly when the engine is turned off.
| End of diagnosis | 1. Low circuit pressure values (insufficient coolant in circuit) | 1. Flush the system and restore the correct charge of fluid and gas Op. 0010T84 COOLANT FOR AIR CONDITIONING SYSTEM - DEHYDRATE AND REPRESSURIZE |
| 2. High circuit pressure values (too much coolant in circuit) | 2. Flush the system and restore the correct charge of fluid and gas Op. 0010T84 COOLANT FOR AIR CONDITIONING SYSTEM - DEHYDRATE AND REPRESSURIZE |
| 3. Pulsing circuit pressure values (compressor discharge valve permanently open) | 3. Replace the compressor Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY  | If the compressor is replaced due to a mechanical problem, remember to clean the entire circuit and change the drier filter. |
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| 2 | CHECK ON FASTENING OF PIPES AND COMPONENTS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| Check that the compressor, the pipes and the system components are correctly fastened. Check the following, in order:- bracket fastening to the engine block;
- fastening of pipes (by bands and spacers)
- no interference between pipes and other components in the engine compartment;
- condenser cleanlineness or damage (presence of mud, foreign bodies).
Also check for cracks in the compressor fastenings to the bracket on the engine block. | Move on to Step 3 | 1. Fastening of components incorrect | 1. Retighten fastenings to torque |
| 2. Interference in the engine compartment | 2. Restore the correct layout of the pipes |
| 3. Condenser obstructed or damaged. | 3. Clean or replace the condenser Op. 5040A40 AIR CONDITIONING CONDENSER - R+R |
| 4. Also check for cracks in the compressor fastenings to the bracket on the engine block. | 4. Replace the compressor Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY |
| 3 | CHECKS TO CARRIED OUT WITHOUT THE COMPRESSOR ON | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| Checks to be carried out without the compressor on:- disconnect the service belt and check for contact between the armature and pulley;
- with the belt disconnected, check for contact between the pulley and external elements.
- check the wear of the pulley bearing by rotating the moving plate in both directions of rotation.
- check whether the compressor magnetic coupling shows signs of overheating.
| Move on to Step 4 | 1. Presence of contact between armature and pulley. | 1. Replace the compressor electromagnetic coupling with pulleyOp. 5040A34 PULLEY WITH COMPRESSOR ELECTROMAGNETIC COUPLING - R+R WITH COMPRESSOR REMOVED |
| 2. Presence of contact between the pulley and external elements. | 2. Remove the contact. |
| 3. Bearing worn | 3. Replace the pulleyOp. 5040A34 PULLEY WITH COMPRESSOR ELECTROMAGNETIC COUPLING - R+R WITH COMPRESSOR REMOVED |
| 4. Signs of overheating on the compressor magnetic coupling | 4. Replace the pulleyOp. 5040A34 PULLEY WITH COMPRESSOR ELECTROMAGNETIC COUPLING - R+R WITH COMPRESSOR REMOVED | If the compressor is replaced due to a mechanical problem, remember to clean the entire circuit and change the drier filter. |
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| 4 | CHECKS TO CARRIED OUT WITH THE COMPRESSOR ON | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| After restoring the correct connection of the service belt, turn the compressor on and off to check:- visually if the compressor magnetic coupling plate slips due to oil or grease on the plate;
- if slippage takes place between the compressor belt and pulley.
| Move on to Step 5 | 1. Oil or grease on the plate. | 1. Clean the oil or grease off the plate and find the oil leak. |
| 2. Slippage between compressor belt and pulley. | 2. Replace the belt |
| 5 | CHECK FOR GAS LEAKS ON THE COMPRESSOR SIDE | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
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| With the engine started and the climate control system at the maximum speed (compressor button ON), place the temperature adjustment knob/button in the maximum cold position, move the probe of the leak detector near the connector to be analyzed and check for any leaks.If there is a leak, repeat the test to make sure that there really is a leak.Withdraw the pipes from the compressor and ensure that the o-rings on the pipes are correctly positioned.Check the condition of the pipe fastening threads on the compressor.With the engine off and the compressor off, bring the leak detector probe up to the compressor pulley near the shaft stem and rear cylinder head gasket to check for leaks. If there is a leak, repeat the test to make sure that there really is a leak.Also check whether the leak is located in other coolant system components. | End of diagnosis | 1. Compressor pipe o-rings poorly positioned (pinching). | 1. Reposition the compressor pipe o-rings correctly. |
| 2. Pipe fastening threads not intact. | 2. Replace the compressor Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY |
| 3. Leak located on shaft stem or compressor rear head. | 3. Replace the compressor Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY |
| 4. Leak located in other cooling system components. | 4. Remove the leak and restore the circuit to correct operation. | If the compressor is replaced due to a mechanical problem, remember to clean the entire circuit and change the drier filter. |
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