DTC P0481: Cooling Fan Control Relay No. 2 Circuit: Description

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The ECM enables low or high engine cooling fan speed by controlling the coil circuit ground for the engine cooling fan relay 2 for low speed (if equipped with two speed fan) and fan relay 1 for high speed. For vehicles equipped with a single speed fan, the ECM will command the cooling fan relay 1 on whenever the Engine Coolant Temperature (ECT) is greater than 210°F (99°C) or if the A/C is commanded on. If A/C is off, the cooling fan will turn off when ECT reaches 205°F (96°C). For vehicles equipped with a two speed fan, high speed will be commanded on if ECT is greater than 102°C (216°F) or A/C high side pressure is above 290 psi (2000 kPa) gauge. High speed will turn off when ECT is below 210°F (99°C) or when A/C high side pressure is less than 189 psi (1300 kPa). When the relay is commanded on the voltage at the ECM should be low (grounded) and high (12 volts) when the relay is commanded off. DTC P0481 will set if the ECM detects that the feedback voltage is below a calibrated value when the cooling fan relay 2 is commanded off.