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Home >> Ford >> 2021 >> Mustang Mach 1, Standard Trans >> Repair and Diagnosis (Single Page) >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Climate Control System - General Information (2 Of 2) >> Diagnosis And Testing >> Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) >> Pinpoint Test(s) >> Pinpoint Test P: The A/C (Air Conditioning) Compressor Relief Valve Discharging
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Pinpoint Test P: The A/C (Air Conditioning) Compressor Relief Valve Discharging

  1. Normal Operation and Fault Conditions 

    The A/C pressure relief valve normal open pressure is 3, 447-4, 137 kPa (500-600 psi).

    Possible Sources 

    • High system pressure
    • A/C pressure relief valve

  2. P1 DIAGNOSE THE A/C (AIR CONDITIONING) COMPRESSOR RELIEF VALVE

    • Start the engine.

    • On the HVAC controls, set the temperature to full cold, select PANEL and select the A/C button (indicator on).

    • Using the appropriate manifold gauge set, check the A/C high side system pressure.

    Is the high side system pressure above the A/C pressure relief valve open pressure [3, 447-4, 137 kPa (500-600 psi)]? 

    Yes  CARRY OUT the refrigerant system tests. REFER to: Refrigerant System Tests - 2.3L EcoBoost (231kW/314PS)/2.3L EcoBoost (257kW/350PS) - MI4 . REFER to: Refrigerant System Tests - 5.0L 32V Ti-VCT . REFER to: Refrigerant System Tests - 5.2L 32V Ti-VCT - Supercharged  . REPAIR the A/C system for a restriction concern found in the refrigerant system tests chart.
     
    No  INSTALL a new A/C compressor. REFER to: Air Conditioning (A/C) Compressor - 2.3L EcoBoost (231kW/314PS)/2.3L EcoBoost (257kW/350PS) - MI4 . REFER to: Air Conditioning (A/C) Compressor - 5.0L 32V Ti-VCT . REFER to: Air Conditioning (A/C) Compressor - 5.2L 32V Ti-VCT - Supercharged