The air conditioning (A/C) pressure sensor is a transducer that varies resistance
according to changes in high side refrigerant pressure. The PCM measures the signal
voltage from the A/C refrigerant pressure sensor, which is a reduced value of the
PCM 5 volt reference. The maximum voltage ranges of the sensor are around 0.1 volts
at 0 psi to 4.9 volts at 443 psi. The sensor input is primarily
used by the PCM to determine when to turn ON the cooling fans. The sensor input also
aids in determining acceptable low/high refrigerant pressure for A/C operation and
idle air control (IAC) position for A/C idle speed. DTC P0530 sets when the
A/C pressure sensor signal voltage at the PCM is above or below the calibrated voltage
value.
Conditions for Setting the DTC
DTC P0530 will set if any of the following conditions exist for 15 seconds:
| • | A/C pressure sensor voltage is less than 0.2 volts (3 psi). |
| • | The IAT is greater than 0°C (32°F). |
| • | DTC P0112 or P0113 has not been set. |
| • | The A/C pressure sensor voltage is less than 0.1 volts (0 psi). |
| • | The IAT is less than 0°C (32°F). |
| • | The A/C pressure sensor voltage is greater than 4.94 volts (446 psi). |
| • | The PCM has received an A/C request from the BCM over serial data. |
| • | The A/C refrigerant pressure sensor voltage is greater than 4 volts
(358 psi). |
| • | The PCM is NOT receiving an A/C request from the BCM over serial data. |
DTC P0530 is a type D DTC.
Diagnostic Aids
If DTC P0122 and P0452 are also set, a short to ground on the 5 volt
reference circuit may exist. Refer to "5 Volt Reference Circuit Error Diagnosis" in
this section.
If actual pressure measured with the A/C gages matches the scan tool, repair
the system, if not within normal system pressure specifications, before diagnosing
this DTC. Retest after the repair has been made.
The PCM will disable the A/C relay if DTC P0530 is active.
Important: The A/C pressure sensor, fuel tank pressure sensor, and TP sensor are all tied
to the same 5 volt reference source.
To locate an intermittent problem, use the scan tool to monitor A/C HIGH SIDE
PRESS. SENSOR voltage with the ignition ON and the engine OFF. Wiggling the wires
while watching for a change in A/C HIGH SIDE PRESS. SENSOR voltage may locate the
area where an open, short to ground, or short to voltage in the wiring could lie.
