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Home >> Mazda >> 2016 >> CX-9 Signature >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting - Engine >> Engine Control System Operation Inspection >> Engine Control System Inspection >> Main Relay Operation Inspection >> Cooling Fan Control System Inspection
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Cooling Fan Control System Inspection

  1. Connect the M-MDS to the DLC-2.
  2. Start the engine and warm it up to normal operating temperature.
  3. Perform the KOER self test. Refer too KOEO/KOER SELF TEST [PCM (SKYACTIV-G 2.5T)] .)
  4. Verify that DTC P0480:00 is not shown and the cooling fan operates during the KOER self test.
    • If the DTC P0480:00 is displayed, perform the DTC inspection. Refer too DTC P0480:00 [PCM (SKYACTIV-G 2.5T)] .)
    • If the cooling fans do not operate, proceed to the following:
      • Inspect the following parts in the indicated order in accordance with fan operation conditions.
        • Open circuit between battery positive terminal and cooling fan relay
        • Open circuit between cooling fan relay and fan control module
        • Open circuit between fan control module and ground
        • Poor connection of the cooling fan relay
        • Poor connection of the fan control module connector
      • If there is no malfunction:
  5. Start the engine and idle it at an engine coolant temperature of less than 97 °C {207 °F}.
  6. Verify that the cooling fan does not operate when the A/C switch is turned off.
    • If the cooling fan operates, perform an inspection of the following:
      • Cooling fan relay (stuck close)
      • Short to power supply in wiring harness between cooling fan relay and fan control module
      • Refrigerant pressure sensor
      • Climate control unit
      • CAN communication (PID: AC_REQ is on constantly)