Cooling Fan System Operation (At Idle)

2010 Mazda 5 Sport, 2.3 L, StandardSECTION Cooling Fan System Operation (At Idle)
WARNING: This page is about a different car, the 2004 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Cooling Fan System Operation At Idle
G01345616Courtesy of MAZDA MOTORS CORP.
  1. Connect the WDS or equivalent to the DLC-2.
  2. Verify that DTC P0480 or P0481 is not displayed.
    • If DTC P0480 and/or P0481 are displayed, perform DTC inspection.
  3. Access the ECT PID.
  4. Verify that the ECT PID is 97°C {208°F} or less. 
  5. Verify that the A/C switch and fan switch are off.
  6. Start the engine and let it idle.
  7. Verify that the cooling fans are not operating.
    • If the cooling fans are operating at low speed, inspect for the following:
      • Cooling fan relay No. 1 (stuck closed)
      • Wiring harnesses and connectors (cooling fan relay No. 1-PCM terminal 5X) (short to GND)
    • If the cooling fan No. 1 is not operating, but cooling fan No. 2 is operating, inspect for the following:
      • Cooling fan relay No. 3 (stuck closed)
      • Wiring harnesses and connectors (cooling fan relay No. 3-PCM terminal 5AD) (short to GND)
  8. Warm up engine 97°C {208°F} or more  and verify that the cooling fans are operating at low speed.
    • If cooling fans are not operating, inspect for the following:
      • Cooling fan relay No. 1 (stuck open)
      • Wiring harnesses and connectors (battery-cooling fan relay No. 1-cooling fan relay No. 2) (open)
      • Wiring harnesses and connectors (main relay-cooling fan relay No. 1 PCM terminal 5X) (open)
    • If cooling fan relay No. 1 is operating at high speed, inspect for the following:
      • Cooling fan relay No. 2 (stuck close)
  9. Stop the engine.
  10. Disconnect the ECT sensor.
    NOTE:
    • When the ECT sensor connector is disconnected, the PCM stores DTC P0118.
  11. Start the engine and let it idle.
  12. Verify that the cooling fans are operating at high speed.
    • If the cooling fans are operating at low speed, inspect for the following:
      • Cooling fan relay No. 2 (stuck open)
      • Cooling fan relay No. 3 (stuck open)
      • Wiring harnesses and connectors (open circuit at battery-cooling fan relay No. 3-cooling fan No. 2-GND)
      • Wiring harnesses and connectors (open circuit at main relay-cooling fan relay No. 2-PCM terminal 5AD)
      • Wiring harnesses and connectors (open circuit at main relay-cooling fan relay No. 3-PCM terminal 5AD)
    • If cooling fan No. 1 is operating at high speed, but cooling fan No. 2 is not operating, inspect for the following:
      • Cooling fan relay No. 3 (stuck open)
      • Wiring harnesses and connectors (open circuit at main relay-cooling fan relay No. 3-PCM terminal 5AD)
    • If cooling fan No. 1 is operating at high speed, but cooling fan No. 2 is not operating, inspect for the following:
      • Cooling fan relay No. 3 (stuck open)
      • Wiring harnesses and connectors (open circuit at main relay-cooling fan relay No. 2-PCM terminal 5AD)
  13. Clear the DTC from the PCM memory.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.