DTC 09

CIRCUIT DESCRIPTION

In the CCOT air conditioning system. the pressure cycling switch informs the control assembly microprocessor of the direct operating condition (cycling) of the compressor. When the refrigeration system becomes low on freon, the on/off frequency of the pressure cycling switch increases. If compressor on time becomes too short the microprocessor will flash a mode touch switch Light Emitting Diode (LED) on the control panel and shut the compressor off until the system is recharged or repaired and the battery reset.

TEST DESCRIPTION

The following numbers refer to circled numbers or the diagnostic chart.

1. Code 09 indicates the refrigeration system is low on freon. Add freon and leak check the system. Refer to Manual A/C. If no leak is found. proceed to step 2.

2. This step will charge the system as necessary so clutch cycles can be monitored. Excess cycling is usually due to a plugged orifice if the system is properly charged. If clutch will not engage, temporarily jumper across the pressure cycling switch to check for an open.

3. If inlet is colder than outlet and system is still not cooling, check for plugged orifice in the expansion tube.

4. This test will determine if adequate freon charge is in system. If inlet and outlet pipes are the same temperature, the system needs additional refrigerant. Refer to Manual A/C.