Bosch ACS 752 Manual página 50

en 50 | ACS 752 | Testing the vehicle air conditioning system
9.3 Diagnosis
!
The ACS 752 diagnostic software was developed
to provide support and instruction for defects in
vehicle air conditioning systems. The diagnosis and
recommendations serve only as a reference and do
not constitute recommended repair instructions.
9.3.1 Diagnosis preparation
!
Park the vehicle in a place where it is protected from
wind and sunlight. Even slight air movement can
falsify the values.
!
Follow the additional ACS 752 menu prompting.
1. Connect the service hoses to the vehicle.
2. Lower the hood without closing it.
3. Start the engine on the vehicle to be tested.
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The engine should have operating temperature.
4. Increase vehicle speed to 1,500 – 2,000 rpm and
hold.
5. Switch on the air conditioning system.
6. Open the fan openings (middle of vehicle).
7. Set vehicle air conditioning system to maximum cool-
ing capacity.
8. Set fan to maximum ventilation.
9. Switch off air circulation.
10. Open doors and windows.
!
Check if the compressor switches on.
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Wait (3 – 5 minutes) until the vehicle air condition-
ing system cools evenly.
!
Measure the ambient temperature properly. Stay at a
distance of approx. 1 m from the vehicle.
!
Measuring in close vicinity of the engine can lead to
a false diagnosis.
11. Measure and record the ambient temperature.
12. High-pressure gage: Read and record the highest
pressure value when the compressor is switched
on.
13. Low-pressure gage: Read and record the lowest
pressure value when the compressor is switched
on.
14. Temperature: Measure and record the mean air
temperature value (at middle fan openings).
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9.3.2 Perform diagnosis
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The diagnosis function works only if a vehicle is se-
lected in the database and when two service hoses
are connected.
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If no vehicle is selected, ACS 752 opens the data-
base and prompts to select a vehicle in order to
perform a diagnosis.
!
Follow the additional ACS 752 menu prompting.
1. Call up the start screen.
2. Press <Menu>.
3. Press <2> for "Functions".
4. Press <3> for "Diagnosis".
 Message is displayed.
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Only 2 service hoses can be entered for diagnosis.
5. Select vehicle from the vehicle database.
6. Apply data.
7. Enter the measured ambient temperature and con-
firm with <OK>.
8. Enter the read pressure value (HP) and confirm with
<OK>.
9. Enter the read pressure value (LP) and confirm with
<OK>.
10. Enter the air temperature measured at the fan
openings and confirm with <OK>.
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Diagnosis:
The entered data is displayed along with the status.
A list of potential causes is displayed along with the
potential solutions.
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Print with <OK>
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Return with <ESC>.
Robert Bosch GmbH