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

DESCRIPTION
•  A/C compressor magnetic clutch does not engage when A/C switch 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 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

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Perform the KOEO or KOER self test.
Are any DTCs displayed?
Yes
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
No
Go to the next step.
2
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?
Yes
Go to the next step.
No
Go to Step 6.
3
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?
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 the A/C relay.
Is there any malfunction?
Yes
Replace the A/C relay.
No
Go to the next step.
5
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?
Yes
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.
No
Repair or replace the wiring harness for a possible open circuit.
6
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?
Yes
Inspect the refrigerant pressure switch operation.
•  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 1AW
•  Open circuit in wiring harness between climate control unit and resistor (if blower motor does not operate)
―  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
Perform the A/C Cut-off Control System Inspection.
Does the A/C cut-off operation work properly?
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, reprogram the PCM if a later calibration is available. Retest.