Cooling Fan Motor Control

The ECM controls the cooling fan motor by grounding the cooling fan relay coil circuit. When the relay coil circuit is grounded, the switch side of the relay closes allowing current to flow to the engine cooling fan motor.

The ECM operates the cooling fan relay based on the reading from the ECT sensor or A/C high side pressure sensor when the A/C relay is commanded On. Under normal operating conditions, the cooling fan operates whenever the ECT is greater than 102°C (216°F), or if the A/C relay is commanded On with the A/C high side pressure above 1247 kPa (181 psi). The cooling fan will turn Off when the ECT drops below 99°C (210°F) or when the A/C high side pressure drops below 824 kPa (120 psi) with the A/C relay commanded On. If the engine is turned Off and the ECT is above 104°C (219°F), the cooling fan can run up to 5 minutes or until the ECT drops below 95°C (203°F). If a low/high ECT circuit fault (DTC P0117 or P0118) is set the ECM will command the cooling fan relay On to protect the engine and transaxle until the condition is corrected.