Operation CHARM: Car repair manuals for everyone.

Initial Inspection and Diagnostic Overview

REFRIGERANT

ON-VEHICLE INSPECTION

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
a. This is a method in witch the trouble is located by using a manifold gauge set. Read the manifold gauge pressure when the these conditions are established.

Test conditions:
- Temperature at the air inlet with the switch set at RECIRC is 30 - 35 °C (86 - 95 °F)
- Engine running at 1500 rpm
- Blower speed control switch at "HI" position
- Temperature control dial at "COOL" position
- A/C switch ON
- Fully open doors




1. Normally functioning refrigeration system.

Gauge reading:
Low pressure side:
0.15-0.25 MPa (1.5 - 2.5 kgf/sq.cm)
High pressure side:
1.37-1.57 MPa (14 - 16 kgf/sq.cm)




2. Moisture present in refrigeration system.




3. Insufficient cooling




4. Poor circulation of refrigerant




5. Refrigerant does not circulate




6. Refrigerant overcharged or insufficient cooling of condenser




7. Air present in refrigeration system




8. Expansion valve improperly




9. Defective compression compressor




Gauge readings (Reference)