3.
Check whether Air-Con pressure is rising during acceclerating.
A/C pressure sensor is installed betweem receiver driver and expansion valve. Sensing refrigerants pressure, this sensor converts pressure into voltage to input the value to PCM. With this signal, PCM performs idle control, cooling fan control, aircon compresser control.
Checking output signals from A/C pressure sensor under detecting condition, if an signal above 4.65V lasts for more than 10 sec., PCM sets P0533.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Detects sensor signal short to high voltage | ● Poor connection ● Short to battery in signal circuit ● Open in ground circuit ● Faulty A/C pressure sensor ● Faulty PCM | |
Enable Conditions | ● Engine works | ||
Thresh old value | ● Sensor output voltage 〉4.65V | ||
Diagnosis Time | ● Continuous (More than 10 seconds failure for every 20 seconds test) | ||
MIL On Condition | ● DTC only (NO MIL ON) | ||
Pressure(psi) | 14.7 | 56.7 | 250 | 439.7 | 465 | |
Voltage(V) | 0.203 | 0.629 | 2.633 | 4.649 | 4.8 | |
Ignition "OFF"
Connect Scantool and Engine "ON"
Check whether Air-Con pressure is rising during acceclerating.
Are those items on scantool displayed correctly ?
▶ Fault is intermittent caused by poor contact in Sensor’s and/or PCM’s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
▶ Go to "Terminal and Connector Inspection" procedure.
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
▶ Go to " Power Circuit Inspection " procedure.
IG Key "OFF".
Disconnect the A/C pressure sensor connector.
IG Key "ON".
Measure the voltage between terminal 3 of A/C pressure sensor harness connector and chassis ground.
Specification : approx. 5V
Is the measured voltage within specification ?
▶ Go to "Ground circuit inspection" procedure.
▶ Repair Open in power circuit and go to "Verification of Vehicle Repair" procedure.
IG Key "OFF".
Disconnect the A/C pressure sensor connector.
IG Key "ON".
Measure the voltage between terminal 3 of A/C pressure sensor harness connector and chassis ground. (Fig A)
Measure the voltage between terminal 3 and terminal 1 of A/C pressure sensor harness connector. (Fig B)
Specification : The Difference between "A" and "B" is below 200mV.
Is the measured voltage within specification ?
▶ Go to "Signal circuit inspection" procedure.
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Voltage inspection
IG Key "OFF".
Disconnect the A/C pressure sensor connector.
IG Key "ON".
Measure the voltage between terminal 2 of A/C pressure sensor harness connector and chassis ground.
Specification : Approx. 0V
Is the measured voltage within specification ?
▶ Go to "Component inspection" procedure.
▶ Go to "Check short to battery in harness" procedure.
Check short to battery in harness
IG Key "OFF".
Disconnect A/C pressure sensor connector and PCM connector.
Measure the resistance between terminal 2 and terminal 3 of A/C pressure sensor harness connector.
Specification : Infinite
Is the measured resistance within specification ?
▶ Go to "Component inspection" procedure.
▶ Repair Short in signal circuit and go to "Verification of Vehicle Repair" procedure.
A/C pressure sensor inspection
IG Key "OFF" and connect the scantool.
Connect the probe to A/C pressure sensor signal and select the oscilloscope in the menu.
Check the waveform with acceleration and deceleration after engine start.
Pressure(psi) | 14.7 | 56.7 | 250 | 439.7 | 465 | |
Voltage(V) | 0.203 | 0.629 | 2.633 | 4.649 | 4.8 | |
Is the measured waveform of A/C pressure sensor normal?
▶ 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.
▶ 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.
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 to reuse the PCM on the others
After a repair, it is essential to verify that the fault has been corrected.
Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
Using a Scantool, Clear the DTCs
Operate the vehicle within conditions noted in the freeze frame data or enable conditions
Monitor that all rediness test have been verified as " Complete "
Are any DTCs present ?
▶ Go to the applicable troubleshoooting procedure.
▶ System is performing to specification at this time.
