From the shop manual:

Normal Pressures for the AC lines are Low Side: 21.3-42.7 psi and High Side: 199.1 to 270.2 psi

Your high side seems fine, so working from the manual on low side:

Symptom: Suction (Low Abnormally High. Gauge) Pressure Low pressure gauge (Low pressure gauge is lowered after condenser is cooled by water.)

Cause: Excessive Refrigerant In System

Fix: Discharge and Recover, Replace Coolent to recommend levels

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Symptom: Suction (Low Abnormally High. Gauge) Pressure Low pressure hose temperature. (Low pressure hose temperature around the com compressor ressor refrigerant line connector is lower than around evaporator.)

Cause: Unsatisfactory valve operation due to defective temperature sensor of expansion valve.

Fix: Replace the expansion valve.

Cause: Expansion valve opens too long.

Fix: Replace the expansion valve.

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Symptom: Suction (Low Abnormally High. Gauge) Pressure High and low pressure gauge balanced quickly. (After turned off A/C)

Cause: Compressor gasket is defective.

Fix: Repair or Replace Compressor

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Symptom: Suction (Low Abnormally Low. Gauge) Pressure, Insufficient cooling.

Cause: Insufficient refrigerant in system.

Fix: Check for leaks. Discharge and recover the refrigerant. Recharge to specified amount.

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Symptom: Suction (Low Abnormally Low. Gauge) Pressure, Frost on the expansion valve inlet line

Cause: Expansion valve clogged.

Fix: Replace the expansion valve.

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As you can see, there are a lo trof variables. A/C systems should be checked by a certified A/C mechanic.