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STEP
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INSPECTION
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RESULTS
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ACTION
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1
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Perform the self-test function using the WDS or equivalent.
Turn the engine switch to the ON position.
Retrieve any DTCs.
Are any DTCs displayed?
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Yes
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DTC is displayed:
Go to the appropriate DTC test.
Communication error message is displayed:
Inspect the following:
• Open circuit between PCM control relay and PCM terminal 119 or 120
• Open circuit PCM control relay and PCM terminal 105
• PCM control relay stuck open
• Open or poor ground circuit (PCM terminal 1, 2, 3, 114 or 117)
• Poor connection to vehicle body ground
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No
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No DTC is displayed:
Go to the appropriate DTC test.
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2
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Start the engine and run it at idle.
Turn the A/C switch on.
Remove the A/C relay.
Does the A/C magnetic clutch disengage?
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Yes
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Inspect the following:
• A/C relay is stuck closed
• Short to ground circuit between A/C relay and PCM terminal 26
If both items are normal, go to the next step.
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No
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Inspect if circuit between A/C relay and magnetic clutch shorts to battery power circuit.
If circuit is normal, inspect magnetic clutch stuck engagement or clearance.
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3
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Start the engine and turn the A/C switch on.
Measure PCM terminal 32 voltage while disconnecting the refrigerant pressure switch connector.
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Note
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• PCM terminal 32 voltage should read B+ when disconnecting the connector. If the PCM terminal 32 voltage reading remains below 1.0 V, a short to ground circuit may be present.
Is the voltage B+?
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Yes
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Inspect for a short to ground circuit between the refrigerant pressure switch and PCM terminal 32.
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No
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Go to the next step.
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4
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Reconnect the refrigerant pressure switch connector. Measure PCM terminal 32 voltage while turning off the A/C switch.
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Note
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• PCM terminal 32 voltage should read B+ when turning the A/C switch off. If the PCM terminal 32 voltage reading remains below 1.0 V, a short to ground circuit maybe present.
Does the voltage remain B+?
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Yes
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Inspect the following:
• Short to ground circuit between A/C switch and A/C amplifier.
• Short to ground circuit between A/C amplifier and refrigerant pressure switch.
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No
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Inspect for a stuck closed A/C switch.
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5
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Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If the malfunction remains, inspect the related Service Information and perform repair or diagnosis.
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- If the vehicle is repaired, troubleshooting completed.
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- If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if later calibration is available. Retest.
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