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Home >> Mazda >> 2024 >> 3 Carbon Turbo, 4D Hatchback >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Symptom Troubleshooting - Heater, Ventilation & Air Conditioning (HVAC) >> No Cool Air >> Diagnostic Procedure

Diagnostic Procedure

NO COOL AIR DIAGNOSTIC PROCEDURE

Step Inspection Results Action
1 VERIFY MALFUNCTION SYMPTOM 
  • Does the malfunction symptom occur only during idling stop?
 Yes Perform malfunction diagnosis according to symptom troubleshooting for i-stop.
(See SYMPTOM TROUBLESHOOTING [SKYACTIV-G] .)
(See SYMPTOM TROUBLESHOOTING [SKYACTIV-G 2.5T] .)
No Go to the next step.
2 VERIFY AIRFLOW CONDITION 
  • Switch the ignition ON (engine off or on) to operate the A/C.
  • Does air flow from the vents? Does air flow from the vents after operating the blower motor?
 Yes Go to the next step.
No Perform malfunction diagnosis according to [INSUFFICIENT AIR (OR NO AIR) BLOWN FROM VENTS] or [AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE].
(See INSUFFICIENT AIR (OR NO AIR) BLOWN FROM VENTS .)
(See AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE .)
3 VERIFY A/C COMPRESSOR OPERATION 
  • Switch the ignition ON (engine on) to operate the A/C.
  • Does the A/C compressor operate?
 Yes Perform malfunction diagnosis according to [AIR FROM VENTS NOT COLD ENOUGH].
(See AIR FROM VENTS NOT COLD ENOUGH .)
No Go to the next step.
4 VERIFY RELATED MODULE DTCs 
  • Perform the DTC inspection for the following modules. (See DTC INSPECTION .)
    • PCM
    • Dash-electrical supply unit
    • Body control module (BCM)
  • Are any DTCs displayed?
 Yes Repair or replace the malfunctioning location according to the applicable DTC troubleshooting.
(See DTC TABLE [PCM (SKYACTIV-G)] .)
(See DTC TABLE [PCM (SKYACTIV-G 2.5T)] .)
(See DTC TABLE [DASH_ESU] .)
(See DTC TABLE [BCM] .)
No Go to the next step.
5 VERIFY MAGNETIC CLUTCH OPERATION 
  • Access the PCM PID [A/C_SW] (SKYACTIV-G or SKYACTIV-G 3.3T)/[A/C_RLY] (SKYACTIV-D) using the M-MDS. (See PID/DATA MONITOR INSPECTION .)
  • Switch the ignition ON (engine off).
  • Turn the PCM simulation item [A/C_SW] (except SKYACTIV-D)/[A/C_RLY] (SKYACTIV-D) on and off using the M-MDS.

    (See SIMULATION INSPECTION .)

  • Is the magnetic clutch engaged/disengaged according to the simulation function operation?
 Yes Go to the next step.
No Go to Step 11.
6 VERIFY MEASURED VALUE OF A/C PRESSURE SENSOR 
  • Access the PCM PID [A/C_PRES_AFT_COMP] and [A/C_PRES_BEF_EXP_VLV] using the M-MDS.

    (See PID/DATA MONITOR INSPECTION .)

  • Turn ON/OFF the air conditioner switch on the climate control unit.
  • Is the monitoring value normal?
 Yes Go to Step 8.
No Go to the next step.
7 VERIFY REFRIGERANT PRESSURE SENSOR FOR MALFUNCTION  Yes Inspect the followings:
Repair or replace the malfunctioning location and perform the repair completion verification 1.
(Refer to A/C COMPRESSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] , or A/C COMPRESSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T] in service information.)
No Replace the refrigerant pressure sensor and perform the repair completion verification 1.
(Refer to Refrigerant Pressure Sensor No. 1 [FULL-AUTO AIR CONDITIONER] , or Refrigerant Pressure Sensor No. 1 [MANUAL AIR CONDITIONER] in service information.)
(Refer to Refrigerant Pressure Sensor No. 2 [FULL-AUTO AIR CONDITIONER] , or Refrigerant Pressure Sensor No. 2 [MANUAL AIR CONDITIONER] in service information.)
8 VERIFY MEASURED VALUE OF EVAPORATOR TEMPERATURE SENSOR 
  • Access the dash-electrical supply unit PID [EVA_TEMP] using the M-MDS. (See PID/DATA MONITOR INSPECTION .)
  • Turn ON/OFF the air conditioner switch on the climate control unit.
  • Is the monitoring value normal?
 Yes Perform the repair completion verification 1.
No Go to the next step.
9 VERIFY EVAPORATOR TEMPERATURE SENSOR FOR MALFUNCTION  Yes Go to the next step.
No Replace the evaporator temperature sensor and perform the repair completion verification 1.
(Refer to EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] , or EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] in service information.)
10(2) INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN DASH-ELECTRICAL SUPPLY UNIT AND EVAPORATOR TEMPERATURE SENSOR FOR MALFUNCTION  Yes Perform the repair completion verification 1.
No Repair or replace the malfunctioning location and perform the repair completion verification 1.
11 DETERMINE IF MALFUNCTION IS CAUSED BY A/C RELAY CIRCUIT MALFUNCTION OR PCM MALFUNCTION 
  • Short the wiring harness between A/C relay terminal E (A/C control signal) and body GND.
  • Is there cool airflow?
 Yes Remove the short and go to the next step.
No Go to Step 13.
12(2) INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN A/C RELAY AND PCM FOR MALFUNCTION  Yes Perform the repair completion verification 1.
No Repair or replace the malfunctioning location and perform the repair completion verification 1.
13 VERIFY MAGNETIC CLUTCH FOR MALFUNCTION  Yes Go to the next step.
No Replace the magnetic clutch and perform the repair completion verification 1.
(Refer to MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY [SKYACTIV-G 2.0, SKYACTIV-G 2.5] , or MAGNETIC CLUTCH INSPECTION [SKYACTIV-G 2.5T] in service information.)
14(2) INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN BATTERY AND A/C RELAY FOR MALFUNCTION  Yes Perform the repair completion verification 1.
No Repair or replace the malfunctioning location and perform the repair completion verification 1.
15(2) INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN IG1 RELAY No. 2 AND A/C RELAY FOR MALFUNCTION  Yes Perform the repair completion verification 1.
No Repair or replace the malfunctioning location and perform the repair completion verification 1.
16(2) INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN A/C RELAY AND MAGNETIC CLUTCH FOR MALFUNCTION  Yes Replace the A/C relay and perform the repair completion verification 1.
(Refer to RELAY LOCATION in service information.)
No Repair or replace the malfunctioning location and perform the repair completion verification 1.
Repair completion verification 1 VERIFY IF MALFUNCTION CAUSE IS CORRECTED 
  • Install/connect the part removed/disconnected during the troubleshooting procedure.
  • Is there cool airflow (is result of refrigerant system performance test normal?)? (Refer to REFRIGERANT SYSTEM PERFORMANCE TEST in service information.)
 Yes Troubleshooting completed.
(Explain repair contents to customer.)
No Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.
(See MALFUNCTION DIAGNOSIS FLOW [CONTROLLER AREA NETWORK (CAN)] .)
If the CAN communication is normal, perform the diagnosis from Step 1.
(1) If the refrigerant has completely leaked out, ambient air may penetrate the refrigerant system and the desiccant in the receiver/drier may absorb moisture in the ambient air resulting in saturation. If the refrigerant system is used under this condition, rust may generate in the A/C compressor due to the moisture, causing secondary problems such as A/C compressor lock or abnormal noise. Therefore, it will be necessary to replace the receiver/drier.

(2) When performing an asterisked (*2 ) troubleshooting inspection, first verify the damage and connection status of the connectors and terminals, then perform the inspection while shaking the wiring harness (cause of malfunction may be due to poor connection of connectors, terminals, or wiring harness). If there is a malfunction in the connectors or terminals, securely connect, repair, or perform replacement.
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