Operation CHARM: Car repair manuals for everyone.

General and Specific System Condition Charts

These charts were developed in a wind tunnel by producing known system problems and recording pressures and temperatures at various ambient temperatures. The tests were then validated using the same vehicle setup in a service environment. To find your system problem, compare the performance test readings to the readings on the charts for your ambient temperature. When all pressure and temperature readings fall within the limits of a given chart use that chart to repair the vehicle. A/C System Performance Test