Air Conditioning (A/C) Diagnostics - Pressure Zone B

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Step	Action	Yes	No
DEFINITION: The low side pressure is higher than normal and the high side pressure is lower than normal. Malfunctioning A/C Compressor Refrigerant Under Charge
1	Were you sent here from the A/C System Performance Test?	Go to Step 2	Go to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series)
2	After continued operation of the air conditioning (A/C) system, do the low and the high side pressures equalize or become static?	Go to Step 5	Go to Step 3
3	Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: CAUTION: Refer to Moving Parts and Hot Surfaces Caution . The low side pressure is equal to or greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series) . The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series) . The low side refrigerant line at the compressor feels cool-to-warm. The high side refrigerant line at the compressor feels warm-to-hot. Do the listed conditions exist?	Go to Step 5	Go to Step 4
4	Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: CAUTION: Refer to Moving Parts and Hot Surfaces Caution . The low side pressure is greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series) . The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series) . The low side refrigerant line at the compressor feels warm. The high side refrigerant line at the compressor feels warm to hot. Do the listed conditions exist ?	Go to Step 5	Go to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series)
5	The A/C system has a low refrigerant charge. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the procedure complete?	Go to Step 6	-
6	Record the low and the high side pressures as well as the instrument panel (I/P) air outlet temperature after you perform the repairs. Compare the pressures and the panel outlet temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test (Short Wheel Base) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 1500 Series) or Air Conditioning (A/C) System Performance Test (Long Wheel Base - 2500 Series) . Are the readings within the specified ranges found on the A/C Performance Chart?	Go to Step 13	Go to Step 7
7	The A/C compressor is malfunctioning. Remove the expansion device and inspect for contamination. Refer to Expansion (Orifice) Tube Replacement (W/O C69) or Expansion (Orifice) Tube Replacement (W/C69) . Did you find metal flakes on the expansion device?	Go to Step 9	Go to Step 8
8	Inspect the expansion device for a brown, powdery residue indicating desiccant in the A/C system. Is a brown, powdery residue present?	Go to Step 11	Go to Step 12
9	Remove the suction and the discharge lines from the compressor. Refer to Suction Hose Replacement (W/O C69) or Suction Hose Replacement (W/C69) and to Discharge Hose Replacement . Inspect for metal flake contamination at the line connections and the compressor ports. Is metal flake contamination present?	Go to Step 10	Go to Step 12
10	Replace the A/C compressor. Refer to Compressor Replacement . Install an A/C refrigerant filter. Refer to Air Conditioning (A/C) Refrigerant Filter Replacement (C69) . Replace the orifice tube. Refer to Expansion (Orifice) Tube Replacement (W/O C69) or Expansion (Orifice) Tube Replacement (W/C69) . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
11	Flush the A/C system. Refer to Flushing . Replace the orifice tube. Refer to Expansion (Orifice) Tube Replacement (W/O C69) or Expansion (Orifice) Tube Replacement (W/C69) . Replace the A/C compressor. Refer to Compressor Replacement . Replace the accumulator. Refer to Accumulator Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
12	Replace the A/C compressor. Refer to Compressor Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
13	Operate the system in order to verify the repair. Did you find and correct the condition?	System OK	Go to Symptoms - HVAC Systems - Automatic