Refrigerant System

- Check A/C refrigerant system pressures.

If system pressures are not correct, refer to conditions/service solutions below:

High pressure remains at base pressure (engine OFF) or only increases slowly; low pressure drops quickly to suction pressure or lower
Low refrigerant charge:
- Check for leaks with leak detector, repair/eliminate as necessary, evacuate and recharge system.

High pressure normal; low pressure corresponds to chart value, proper cooling performance is not obtained.

Low refrigerant charge:
- Check for leaks with leak detector, repair/eliminate as necessary, evacuate and recharge system.

High pressure increases only slightly over base pressure (engine OFF); low pressure drops only slightly
A/C compressor malfunctioning:
- Replace A/C compressor.

High pressure above specified value; low pressure drops to suction pressure or lower
A/C system line/hose kinked or plugged:
- Feel A/C system lines/hoses (high and low side) for temperature drop (restriction).
- Inspect all lines/hoses for kinks or damage.
- Replace components as necessary.

High and low pressure normal; after A/C operates for a time, high pressure increases above specified value and low pressure drops to suction pressure or lower
Moisture in system, restrictor icing up:
- Discharge A/C system.
- Replace accumulator and restrictor.
- Evacuate and recharge A/C system.

Low (suction) pressure too low; low pressure switch -F73- switches A/C compressor OFF, proper cooling performance is attained
- Check switching pressures of A/C refrigerant low pressure switch -F73-, replace switch if malfunctioning.
If switching pressures OK, A/C compressor malfunctioning:
- Replace A/C compressor.

Low (suction) pressure too low; low pressure switch -F73- switches A/C compressor OFF, proper cooling performance is not attained
Low refrigerant charge:
- Check for leaks with leak detector, repair/eliminate as necessary, evacuate and recharge system.
- Check switching pressures of A/C refrigerant low pressure switch -F73-, replace switch if malfunctioning. Low (suction) pressure too low; A/C control head -E87- switches A/C compressor OFF (air intake temperature to fresh air blower from evaporator lower than -3 °C (27 °F)
Internal pressure regulation in A/C compressor not correct:
- Replace A/C compressor.