Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2016 Mazda 5 GS, Automatic TransFACTORY OEM SERVICE PROCEDURE
Cooling Fan Control System Inspection
- Connect the M-MDS to the DLC-2.
- Perform the KOEO or KOER self test and verify that DTCs P0117:00, P0118:00, P0480:00 and/or P0481:00 are not shown using the KOEO and/or KOER self test. (See KOEO/KOER SELF TEST
.)
- If DTCs P0117:00, P0118:00, P0480:00 and/or P0481:00 are shown, perform the applicable DTC troubleshooting procedure. (See DTC P0117:00 .) (See DTC P0118:00 .) (See DTC P0480:00 .) (See DTC P0481:00 .)
- Start the engine and let it at idle with ECT is below 97°C {207°F}.
- Verify that the cooling fans are not operating when A/C switch and fan switch are turned off.
- If the cooling fan is operating, inspect for the following based on cooling fans status:
Cooling fan status Inspection item Cooling fan No. 1 Cooling fan No. 2 Low Low - Cooling fan relay No. 1 (Stuck close)
High High - PCM PID AC_REQ is always ON.
- Climate control unit
- CAN communication
Stop High - Cooling fan relay No. 3 (Stuck close)
- Using the M-MDS simulation function, turn FAN1 from the off position to the ON position, and verify that cooling fans No. 1 and No. 2 operate at low speed.
- If the operation could not be confirmed, inspect for the following based on cooling fans status:
Cooling fan status Inspection item Cooling fan No. 1 Cooling fan No. 2 Stop Stop - Cooling fan relay No. 1 (Stuck open)
- Cooling fan No. 1 (Internal circuit open)
- Cooling fan No. 2 (Internal circuit open)
- Wiring harness in battery-cooling fan relay No. 1-cooling fan No. 1 (Open circuit, Fuse is blown by short to ground)
- Wiring harness in cooling fan No. 1-cooling fan relay No. 3-cooling fan No. 2 (Open circuit)
- Wiring harness in cooling fan No. 2-body ground (Open circuit)
High Stop - Cooling fan relay No. 2 (Stuck close)
- Wiring harness in cooling fan No. 1-cooling fan relay No. 3-cooling fan No. 2 (Short to ground) (1)
(1) The fuse between battery and cooling fan relay No. 3 may be burnt out. - Using the M-MDS simulation function, turn FAN1 and FAN2 from the off position to the ON position, and verify that cooling fans No. 1 and No. 2 operate at high speed.
- If the operation could not be confirmed, inspect for the following based on cooling fans status:
| Cooling fan status | Inspection item | |
|---|---|---|
| Cooling fan No. 1 | Cooling fan No. 2 | |
| Stop | High |
|
| High | Stop |
|
Factory Service Tools
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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.
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