System Pressure Fault Classification
WARNING: This page is about a different car, the 2002 Jaguar XKR and 2002 Jaguar XK8. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If erratic or unusual gauge movements occur, check the equipment against a known (calibrated) manifold gauge set.
This table should be used in conjunction with the graphical representations of 'High side' pressure / ambient temperature and 'Low side' pressure / evaporator temperature.
PRESSURE FAULT CLASSIFICATION
| Low side gauge reading | High side gauge reading | Fault | Cause |
|---|---|---|---|
| Normal | Normal | Discharge air initially cool then warms up | Moisture in system |
| Normal to low | Normal | As above | As above |
| Low | Low | Discharge air slightly cool | Refrigerant charge low |
| Low | Low | Discharge air warm | Refrigerant charge very low |
| Low | Low | Discharge air slightly cool or frost build up at expansion valve | Expansion valve stuck closed |
| Low | Low | Discharge air slightly cool, sweating or frost after point of restriction | Restriction in High side of system |
| High | Low | Compressor noisy | Defective compressor reed valve |
| High | High | Discharge air warm and high side pipes hot | Refrigerant charge high or inefficient condenser cooling due to air flow blockage or engine cooling fans not working |
| High | High | Discharge air warm / Sweating or frost at evaporator | Expansion valve stuck open |