Fan Control Module Inspection
- 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