NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZR 1.3, MZR 1.5]

id0103d7802900

23

A/C DOES NOT WORK SUFFICIENTLY
DESCRIPTION
•  The A/C compressor magnetic clutch does not engage when the A/C is turned on.
POSSIBLE CAUSE
•  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 ignition switch
•  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
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
VERIFY PCM DTC
•  Retrieve any continuous memory DTCs using the M-MDS.
•  Are there any continuous memory DTCs displayed?
Yes
Continuous memory DTC is displayed:
•  Go to the applicable DTC inspection.
Communication error message is displayed:
•  Inspect the following:
―  Open circuit in wiring harness between main relay terminal B and PCM terminal 1AJ
―  Open circuit in wiring harness between main relay terminal D and PCM terminals 1BB
―  Open circuit in wiring harness between main relay terminal D and PCM terminals 1BG (ATX)
―  Main relay is stuck open.
―  Open or poor PCM ground circuit (PCM terminals 2AZ, 2BA, 2BB, 2BD and 2BH)
―  Poor connection of vehicle body ground
•  Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
2
DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNETIC CLUTCH DRIVE SIGNAL
•  Access the PCM PID AC_REQ using the M-MDS.
•  Monitor the AC_REQ PID while turning on and off the air conditioner by switching the control panel.
•  Is the AC_REQ PID normal?
Yes
Go to the next step.
No
Go to Step 6.
3
DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH POWER SUPPLY, MAGNETIC CLUTCH GROUND OR MAGNETIC CLUTCH
•  Start the engine and warm it up completely.
•  Turn the ACCS PID 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?
Yes
Inspect for ground condition of the magnetic clutch on the A/C compressor.
•  If ground condition is normal:
―  Inspect the magnetic clutch coil for an open circuit.
―  Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
4
INSPECT A/C RELAY
•  Inspect the A/C relay.
•  Is there any malfunction?
Yes
Replace the A/C relay.
No
Go to the next step.
5
INSPECT A/C RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT
•  Turn the ignition switch 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 1AN (wiring harness-side).
•  Is there continuity?
Yes
Inspect for continuity between the following terminals (wiring harness-side):
•  Ignition switch—A/C relay terminal A
•  Battery positive terminal—A/C relay terminal C
•  A/C relay terminal D—A/C magnetic clutch terminal A
Repair or replace the malfunctioning part according to the inspection results.
No
Repair or replace the wiring harness for a possible open circuit.
6
DETERMINE IF MALFUNCTION CAUSE IS REFRIGERANT PRESSURE SWITCH OR CLIMATE CONTROL UNIT
•  Disconnect the refrigerant pressure switch connector.
•  Connect a jumper wire between refrigerant pressure switch terminals (wiring harness-side).
•  Turn the ignition switch to the ON position (engine off).
•  Turn the A/C switch on and set the blower fan at any speed.
•  Measure the voltage at the PCM terminal 1AO (wiring harness-side).
•  Is the voltage below 1.0 V?
Yes
Inspect the refrigerant pressure switch operation.
(See REFRIGERANT PRESSURE SWITCH INSPECTION [FULL-AUTO AIR CONDITIONER].)
(See REFRIGERANT PRESSURE SWITCH INSPECTION [MANUAL AIR CONDITIONER].)
•  If there is no malfunction:
―  Go to the next step.
No
Inspect the following:
•  Open circuit in wiring harness between refrigerant pressure switch and PCM terminal 1AO
•  Open circuit in wiring harness between climate control unit and resistor (if blower motor does not operate)
•  Evaporator temperature sensor
―  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
―  If there is no malfunction:
•  Replace the climate control unit. (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal)
7
INSPECT A/C CUT-OFF CONTROL SYSTEM OPERATION
•  Perform the A/C Cut-off Control System Inspection.
•  Is there any malfunction?
Yes
Inspect the following:
•  Refrigerant charging amount
•  Seized A/C compressor
Repair or replace the malfunctioning part according to the inspection results.
No
Repair or replace the malfunctioning part according to the inspection results.
8
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.
―  If the vehicle is repaired, troubleshooting is completed.
―  If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.