B1347

CIRCUIT DESCRIPTION
The HVAC control processor monitors the A/C refrigerant charge through the A/C refrigerant low temperature sensor. The HVAC control processor detects low system refrigerant capacity by monitoring a change in the low temperature sensor during the A/C compressor clutch engagement. If the refrigerant charge is too low, the refrigerant boils immediately after passing through the orifice tube. This action creates a large, rapid change in the A/C refrigerant low temperature sensor reading. The message LOW REFRIGERANT-A/C OFF will be displayed on the DIC. If the DTC sets, the A/C compressor clutch will disengage.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON and the engine is running.

CONDITIONS FOR SETTING THE DTC
The HVAC control processor detects a rapid change in the signal circuit of the A/C refrigerant low temperature sensor.

ACTION TAKEN WHEN THE DTC SETS
^ The system disables the A/C compressor until the DTC is cleared.
^ The system displays the LOW REFRIGERANT-A/C OFF message on the DIC.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the HVAC control processor no longer detects a condition.
^ The history DTC clears after 50 fault-free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-3:

Steps 4-12:

The numbers below refer to the step numbers on the diagnostic table.
2. Verify the ambient air temperature and the refrigerant level before continuing with the diagnostics of the DTC.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range.