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Procedure 2 - Ambient Temperature Above 38°C (100°F)

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NOTE: The system performance can be evaluated and diagnosed by analysis of the compressor suction and discharge pressures. The following procedure is used to determine if the system is operating at normal pressures.
NOTE: The procedure varies depending on the ambient (shop) temperature. If the ambient temperature is 38°C (100°F) or lower, follow Procedure 1. If the ambient temperature is over 38°C (100°F), follow Procedure 2.
  1. Drive the vehicle or run the engine until it reaches normal operating temperature.
  2. Connect a R-134a Manifold Gauge Set or R-134a Refrigerant Management Machine with high-pressure and low-pressure gauges to the refrigerant system.
  3. Set the climate controls.
    • If equipped with manual climate control, set the A/C controls for normal A/C-PANEL mode, full COOL temperature, FRESH air, MED-LO blower. If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
    • If equipped with EATC, set temperature to 15°C (60°F) (lowest possible temperature setting). Manually set blower to MED-LO (3 to 4 bars). If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
    • If the vehicle is equipped with auxiliary climate control, set the auxiliary controls to full COOL in the PANEL mode at MED-LO blower speed.
  4. Open all vehicle windows and leave the hood open for the test. Open the rear hatch and/or rear doors (if equipped).
  5. Confirm the compressor clutch is engaged and the engine cooling fan(s) are operating or engaged. Allow the vehicle to idle until the suction (low-side) and discharge (high-side) pressures are stable or fluctuate in a range that repeats.
  6. Record the ambient (shop) temperature.
  7. Record the discharge pressure. If the pressure is fluctuating, record the average value.
  8. Determine if the discharge pressure falls within the normal operating limits using the Normal Refrigerant Discharge Pressures chart.
    Fig 1: Normal Refrigerant Discharge Pressures Chart
    G06457667Courtesy of FORD MOTOR CO.
  9. Record the suction pressure. If the pressure is fluctuating, record the average value.
  10. Determine if the suction pressure falls between normal operating limits using the Normal Refrigerant Suction Pressures chart.
    Fig 2: Normal Refrigerant Suction Pressures Chart
    G06172221Courtesy of FORD MOTOR CO.
  11. Proceed to the DIAGNOSTIC TABLE .
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