Fuel System

COMPONENT LOCATION







GENERAL DESCRIPTION

The PCM(Engine Control Module) receives pressure signal in the A/C refrigerant high pressure side from the A/C refrigerant pressure sensor. This input indicates how much load the A/C compressor is putting on the engine and is one of the factors used by the PCM in order to determine the idle air control position for the idle speed. The circuits consist of a 5V reference and a ground, both provided by the PCM, and a signal from the sensor. The signal is a voltage which is proportional to the A/C pressure from 0 to 5V. Low pressure produces a low voltage signal and high pressure a high-voltage signal.


DTC DESCRIPTION

Checking output signals from A/C pressure sensor under detecting condition, if an signal below 0.25V lasts for more than 10 sec., PCM sets P0532.


DTC DETECTING CONDITION








SIGNAL WAVEFORM AND DATA







SPECIFICATION








SCHEMATIC DIAGRAM







MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.




(5) Is "Present" Fault displayed?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.


TERMINAL AND CONNECTOR INSPECTION

1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to " Power Circuit Inspection " procedure.


POWER CIRCUIT INSPECTION

1. Key "OFF".
2. Disconnect the A/C pressure sensor connector.
3. Key "ON".
4. Measure the voltage between terminal 3 of A/C pressure sensor harness connector and chassis ground.

Specification : approx. 5V






5. Is the measured voltage within specification ?
YES
> Go to "Signal circuit inspection" procedure.
NO
> Repair Open or Short to ground in A/C pressure sensor power circuit and go to "Verification of Vehicle Repair" procedure.


SIGNAL CIRCUIT INSPECTION

1. Check short to ground inspection
(1) IG Key "OFF".
(2) Disconnect A/C pressure sensor and PCM connector.
(3) Measure the resistance between terminal 2 of A/C pressure sensor harness connector and chassis ground.

Specification : Infinite






(4) Is the measured resistance within specification ?
YES
> Go to "Check open in harness" procedure.
NO
> Repair Short to ground in A/C pressure sensor signal circuit and go to "Verification of Vehicle Repair" procedure.
2. Check open in harness
(1) IG Key "OFF".
(2) Disconnect A/C pressure sensor and PCM connector.
(3) Measure the resistance between terminal 2 of A/C pressure sensor harness connector and terminal 32 of PCM harness connector.

Specification : Approx. below 1Ohms






(4) Is the measured resistance within specification ?
YES
> Go to "Component inspection" procedure.
NO
> Repair Open in A/C pressure signal circuit and go to "Verification of Vehicle Repair" procedure.


COMPONENT INSPECTION

1. A/C pressure sensor inspection
(1) IG Key "OFF" and connect the scantool.
(2) Connect the probe to A/C pressure sensor signal and select the oscilloscope in the menu.
(3) Check the waveform with acceleration and deceleration after engine start.
Specification :









(4) Is the measured waveform of A/C pressure sensor normal?
YES
> Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
NO
> Substitute with a known - good A/C pressure sensor and check for proper operation. If the problem is corrected, replace A/C pressure sensor and go to "Verification of Vehicle Repair" procedure.

NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function before reusing the PCM



VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Press F5(INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is "History (Not Present)" fault displayed?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.