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

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
DEFINITION: The low side pressures is higher than normal and the high 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
2	After continued operation of the A/C system, do the low and 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 & HOT SURFACES CAUTION in Cautions and Notices. The low side pressure equal to or above the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is below the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . 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 & HOT SURFACES CAUTION in Cautions and Notices. The low side pressure is above the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is below the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . 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
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 high side pressures as well as the I/P outlet air temperature after repairs are performed. Compare the pressures and outlet temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the readings within the specified ranges?	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 (Body VIN Code 3) Expansion (Orifice) Tube Replacement (Body VIN Code 6) . Are there 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 there a brown, powdery residue present?	Go to Step 11	Go to Step 12
9	Remove the compressor hose from the compressor. Refer to Compressor Hose Assembly Replacement (Body VIN Type 3) Compressor Hose Assembly Replacement (Body VIN Type 3) . Inspect for metal flake contamination at the line connections and the compressor ports. Is there metal flake contamination present?	Go to Step 10	Go to Step 12
10	Replace the A/C compressor. Refer to Compressor Replacement (Body Type VIN 3) . Replace the orifice tube. Refer to Expansion (Orifice) Tube Replacement (Body VIN Code 3) Expansion (Orifice) Tube Replacement (Body VIN Code 6) . 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 (Body VIN Code 3) Expansion (Orifice) Tube Replacement (Body VIN Code 6) . Replace the A/C compressor. Refer to Compressor Replacement (Body Type VIN 3) . 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 (Body Type VIN 3) . 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 - MANUAL in HVAC - Manual OR Go to SYMPTOMS - HVAC SYSTEMS - AUTOMATIC in HVAC - Automatic