NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZR 1.8, MZR 2.0, MZR 2.5]
id0103d4802900
23 |
A/C DOES NOT WORK SUFFICIENTLY |
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DESCRIPTION
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• A/C compressor magnetic clutch does not engage when A/C switch is turned on.
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POSSIBLE CAUSE
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• Improper refrigerant charge amount
• Open A/C compressor magnetic clutch
• Open circuit in wiring harness between A/C relay and PCM
• Open circuit in wiring harness between A/C relay and battery
• Open circuit in wiring harness between A/C relay and BCM terminal 1B
• Open circuit in wiring harness between A/C relay and A/C magnetic clutch
• Poor ground of A/C magnetic clutch
• Improper A/C magnetic clutch clearance
• Refrigerant pressure switch is stuck open
• Evaporator temperature sensor malfunction
• Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal)
• A/C relay is stuck open
• Improper A/C cut-off control
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Diagnostic procedure
STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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Perform the KOEO or KOER self test.
Are any DTCs displayed?
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Yes
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DTC is displayed:
• Go to the applicable DTC inspection.
Communication error message is displayed:
• Open circuit in wiring harness between main relay terminal B and PCM terminal 1Q
• Open circuit in wiring harness between main relay terminal C and PCM terminals 1A, 1B
• Main relay is stuck open.
• Open or poor ground circuit (PCM terminals 1E, 1F, 1G and 1BE)
• Poor connection of vehicle body ground
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No
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Go to the next step.
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2
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Access the PCM PID AC_REQ using the M-MDS.
Monitor the PCM PID AC_REQ while turning on and off the air conditioner by switching the control panel.
Is the AC_REQ PID normal?
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Yes
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Go to the next step.
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No
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Go to Step 6.
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3
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Start the engine and warm it up completely.
Turn the PCM PID ACCS to ON from OFF using the M-MDS simulation function.
Measure the voltage at the magnetic clutch terminal A (wiring harness-side).
Is the voltage 10.5 V or more?
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Yes
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Inspect for ground condition of the magnetic clutch on the A/C compressor.
• If ground condition is normal:
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No
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Go to the next step.
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4
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Inspect the A/C relay.
(See RELAY INSPECTION.)
Is there any malfunction?
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Yes
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Replace the A/C relay.
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No
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Go to the next step.
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5
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Switch the ignition to off.
Remove the A/C relay.
Disconnect the PCM connector.
Inspect for continuity between A/C relay terminal E (wiring harness-side) and PCM terminal 1I (wiring harness-side).
Is there continuity?
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Yes
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Inspect for continuity between the following terminals (wiring harness-side):
• BCM terminal 1B—A/C relay terminal A
• Battery positive terminal—A/C relay terminal D
• A/C relay terminal C—A/C magnetic clutch terminal A
Repair or replace the malfunctioning part according to the inspection results.
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No
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Repair or replace the wiring harness for a possible open circuit.
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6
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Disconnect the refrigerant pressure switch connector.
Connect a jumper wire between refrigerant pressure switch terminals (wiring harness-side).
Switch the ignition to ON (engine off).
Turn the A/C switch on and set the blower fan at any speed.
Measure the voltage at the PCM terminal 1AW (wiring harness-side).
Is the voltage below 1.0 V?
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Yes
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Inspect the refrigerant pressure switch operation.
• If there is no malfunction:
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No
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Inspect the following:
• Open circuit in wiring harness between refrigerant pressure switch and PCM terminal 1AW
• Open circuit in wiring harness between climate control unit and resistor (if blower motor does not operate)
• Evaporator temperature sensor
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7
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Perform the A/C Cut-off Control System Inspection.
Does the A/C cut-off operation work properly?
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Yes
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Inspect the following:
• Refrigerant charging amount
• Seized A/C compressor
Repair or replace the malfunctioning part according to the inspection results.
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No
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Repair or replace the malfunctioning part according to the inspection results.
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8
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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 the repair or diagnosis.
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