For 1990-2009 cars only
DTC Descriptors
DTC P0530: Air Conditioning (A/C) Refrigerant Pressure Sensor CircuitDTC P0531: Air Conditioning (A/C) Refrigerant Pressure Sensor Performance
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
A/C Refrigerant Low Pressure Switch Signal Circuit | P0530 | P0531 | P0531 | -- |
Low Reference Circuit | -- | P0531 | -- | -- |
Circuit/System Description
The A/C low pressure switch protects the A/C system. The A/C low pressure switch is a 2-wire normally closed switch. The A/C low pressure switch opens the A/C low pressure switch signal circuit and disables the A/C compressor when line pressure falls below 152 kPa (22 psi). The switch will then close once the pressure reaches 303 kPa (44 psi).
Conditions for Running the DTC
| • | Engine is running. |
| • | Any of the conditions for setting the DTC are met for 15 seconds. |
| • | Battery voltage is between 11-18 volts. |
Conditions for Setting the DTC
The ECM detects that the A/C pressure is less than 152 kPa (22 psi).
Action Taken When the DTC Sets
| • | The ECM will not illuminate the malfunction indicator lamp (MIL) |
| • | The ECM stores the Failure Records. |
| • | The A/C compressor clutch is disabled. |
Conditions for Clearing the DTC
| • | The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction. |
| • | The DTC will become history if the ECM no longer detects a failure. |
Diagnostic Aids
A malfunction within the refrigerant system causing high pressure can cause this DTC to set.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the A/C pressure switch harness connector.
- Ignition OFF, test for less than 1 ohm of resistance between the ground circuit and ground.
- Install a 3-amp fused jumper wire between the signal circuit and the ground circuit. Verify the scan tool Pressure Switch parameter is Low Pressure.
- If all circuits test normal, test or replace the A/C Pressure switch.
| ⇒ | If greater than 1 ohm, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Repair Instructions
