LEMON Manuals: Even more car manuals for everyone
Home >> Cadillac >> 2000 >> Seville SLS >> Repair and Diagnosis >> External Pages >> Different car >> Section 28 (HVAC Systems - Automatic) >> Performance Tests >> A/C Performance Test >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Cadillac Seville. However, it is still accessible from the selected car via links, so may be relevant.
  1. Park the vehicle inside or in the shade. Open the windows in order to ventilate the interior of the vehicle. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes. Turn ignition off. Install the ACR 2000 Air Conditioning Service Center. Record the ambient air temperature displayed. Record the low and high side static pressure readings. Are both the low side and high side pressures within the specified value?
    • More than 60°F (16°C) - 50 psi (345 kPa).
    • More than 75°F (24°C) - 70 psi (483 kPa).
    • More than 90°F (33°C) - 100 psi (690 kPa).
    If so, go to next step. If not, check system for leaks. See LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
  2. Close the vehicle doors and windows. Open the driver door window 5-6 in (127-152 mm). Select the following HVAC control settings:
    • A/C On
    • Recirculation Mode
    • Maximum Blower Speed
    • Air Directed Through I/P Panel Outlets
    • All A/C Outlets Open
    • Coldest Temperature Setting
    Install the temperature probes of the ACR 2000 Air Conditioning Service Center in the left and right center A/C air outlets. Apply the parking brake. Place the transaxle in Park. Start the engine. Operate the A/C system for 5 minutes. Inspect A/C components for abnormal frost areas or unusual noises. Press the reset button, before using the print function of the ACR 2000 Air Conditioning Service Center. Print the following information:
    • Outlet Air Temperatures
    • Low-Side Pressure
    • High-Side Pressure
    Compare the low and high side pressures and the output temperatures to the table. See Fig 1. Does all the data recorded fall within the specified ranges of the table? If so, go to step  4. If not, go to next step.
  3. If the pressures and temperatures recorded do not fall within the specified ranges, continue to operate the A/C system for an additional 5 minutes. Reset the ACR 2000 Air Conditioning Service Center and record the pressures and temperatures again. Compare the low and high side pressures and the output temperature to the table. See Fig 1. Does all the data recorded fall within the specified ranges of the table? If so, go to step  8. If not, go to next step.
  4. Do the high and low side pressures fall within the specified ranges, but the outlet temperatures do not? If so, see A/C PRESSURE ZONE "A" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  5. Is the low side pressure greater than the specified range, but the high side pressure within or less than the specified range? If so, see A/C PRESSURE ZONE "B" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  6. Are the low and high side pressures both greater than the specified ranges? If so, see A/C PRESSURE ZONE "C" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  7. Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range? If so, see A/C PRESSURE ZONE "D" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  8. Operate the system in order to verify the test results. Did you find the same results? If so, system is okay. If not, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
Fig 1: A/C Performance Table
G00194615Courtesy of GENERAL MOTORS CORP.
scientia non olet · About LEMON Manuals