LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (HVAC Systems - Manual) >> System Tests >> A/C Pressure Zone "A" Diagnosis

A/C Pressure Zone "A" Diagnosis

WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
NOTE: Definition: The high and low side pressures may be normal or slightly less than normal.
  1. Were you sent here from the A/C System Performance Test? If so, go to next step. If not, see A/C PERFORMANCE TEST .
  2. Refer to the air outlet temperatures recorded during the A/C system performance test. Is the difference in the discharge air temperature between the right and left center A/C outlets greater than 2- 3 degrees? If so, go to step  7. If not, go to next step.
  3. Did the customer concern mention that the A/C system output temperatures are good at first, but then turn warm during extended drives? If so, go to next step. If not, go to step  5.
  4. Increase engine speed to 2000 RPM. During extended operation of the A/C system, does the low side pressure decrease, possibly accompanied by heavy frost on the liquid line between the orifice tube and the evaporator? If so, see A/C PRESSURE ZONE "D" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  5. Refer to the pressures recorded during the A/C system performance test. Inspect for the following conditions:
    • The high side pressure slightly above the specified pressure ranges, but still within zone A. See Figure-Figure .
    • The discharge line is hot.
    • The suction line is cool.
    If the listed conditions exist, go to step  7. If not, go to next step.
  6. Refer to the pressures recorded during the A/C PERFORMANCE TEST . Inspect for the following conditions:
    • High side pressure slightly above the specified pressure ranges, but still within zone A. See Figure-Figure .
    • The discharge line is hot.
    • The suction line is cool.
    Do the listed conditions exist? If so, go to step  6. If not, see TOO HOT IN VEHICLE  under SYMPTOM TESTS.
  7. The A/C system may be undercharged. Leak test A/C system. See LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Recharge the A/C system to specifications. See appropriate RECOVERY, EVACUATION & RECHARGING article in GENERAL SERVICING PROCEDURES. Is the repair complete? If so, go to step  14.
  8. The A/C system may be contaminated. View the ACR 2000 Air Conditioning Service Center information screen for detection of foreign gases in the A/C system. Do foreign gases exist? If so, go to next step. If not, go to step  10.
  9. Evacuate the A/C system to a scavenging tank. See RECOVERY EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Recharge the A/C system to specifications. After repairs are complete, go to step  15.
  10. The A/C system may contain too much moisture or air. Evacuate and recharge the A/C system to specifications. See RECOVERY EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Operate the A/C system and check the outlet air temperatures. See A/C PERFORMANCE TEST . Are the outlet temperatures within the specified ranges of the A/C Performance Test Table? See Figure-Figure . If so, go to step  15. If not, go to next step.
  11. The A/C system may contain too much refrigerant oil. Recover the refrigerant from the A/C system. See RECOVERY EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Remove the accumulator. See ACCUMULATOR  under REMOVAL & INSTALLATION. Drain and measure the refrigerant oil from the accumulator. Is the amount of refrigerant oil drained from the accumulator greater than 5 ounces? If so, go to next step. If not, go to step  13.
  12. Reinstall the accumulator. See ACCUMULATOR  under REMOVAL & INSTALLATION. Flush the A/C system. See FLUSHING PROCEDURES in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Add the specified amount of refrigerant oil to the A/C system. See SPECIFICATIONS . Recharge the A/C system. See RECOVERY EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step  15.
  13. Add the specified amount of refrigerant oil to the A/C system. See SPECIFICATIONS . Install the accumulator. See ACCUMULATOR  under REMOVAL & INSTALLATION. Recharge the A/C system. See RECOVERY EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step  15.
  14. Record the low and high side pressures and the A/C outlet air temperature. Compare the outlet temperatures to those listed in the A/C system performance chart. See Figure-Figure . Are the high and low side pressures and outlet temperatures within specifications? If so, go to next step. If not, see A/C PERFORMANCE TEST .
  15. Operate the system in order to verify the repair. Did you find and correct the condition? If so, system is okay. If not, go to step  2.
scientia non olet · About LEMON Manuals