B1348

CIRCUIT DESCRIPTION

In the process of controlling the compressor clutch, the heater and A/C programmer monitors certain system inputs for an indication of low refrigerant charge. The heater and A/C programmer monitors the normally closed low refrigerant pressure switch at pin D14. The status of the low pressure switch is checked prior to compressor engagement. If the switch opens, the heater and A/C programmer sets DTC B1348 and the message VERY LOW REFRIGERANT - A/C COMPRESSOR OFF will be displayed on the driver information center (DIC). If a DTC B1348 is set, the compressor clutch will disengage and remain disengaged until DTC B1348 is cleared.

FAILURE CONDITIONS

1. Low refrigerant pressure switch remains open for several minutes.
2. Vehicle must be traveling above 48 km (30 mph) of at least 30 seconds. This code may never set at idle or in city traffic.

ACTION TAKEN

1. Disables compressor until DTC is cleared.
2. Displays VERY LOW REFRIGERANT - A/C COMPRESSOR OFF message on DIC.

TEST DESCRIPTION

1. Checks current state of low pressure switch.
2. Checks circuits to low pressure switch.
3. Checks HVAC refrigerant system pressure.
4. Checks for a restriction in refrigerant system.
5. Checks for intermittent short or open.