Fan Control Module Inspection
WARNING: This page is about a different car, the 2017 Mazda CX-9. However, it is still accessible from the selected car via links, so may be relevant.
- Connect the M-MDS to the DLC-2.
- Start and warm up the engine.
- Monitor the engine coolant temperature with the M-MDS.
- Using the simulation function, gradually increase the FAN_DUTY value from 0% to 95%. (See ON-BOARD DIAGNOSTIC TEST
.)
- Visually verify that the operation speed of the cooling fan conforms to the override drive.
- To start the cooling fan from the stopped condition, approx. 5 s. are needed for start-up preparations before starting the cooling fan.
- Using the M-MDS, change the operation condition of the A/C while measuring the engine coolant temperature under the following conditions, and verify that the cooling fan operates correctly.
- Because there is an intake air temperature decrease control setting, the cooling fan may operate when IAT sensor No. 1 detects 60 °C {140 °F} or more according to conditions other than those mentioned.
- Because there is an engine protection control setting, the cooling fan may operate when IAT sensor No. 2 detects 70 °C {158 °F} or more according to conditions other than those mentioned.
Engine coolant temperature °C {°F} A/C operation status Cooling fan operation status less than 98 {208} Off Off less than 98 {208} On On more than 100 {212} Off On - If normal operation cannot be verified in Steps 4 and 5, inspect the input signals of the following parts. Replace the cooling fan motor if all the following parts are normal.
- ECT sensor
- Refrigerant pressure sensor