DTC P0480: Cooling Fan Control Relay Circuit No. 1: 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.

NOTE: Some early production vehicles are only equipped to operate cooling fan relay 1. Therefore, only high cooling fan speed is available on these vehicles.

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 and both fan relay 1 and fan relay 2 for high speed. The ECM will command low fan speed whenever the Engine Coolant Temperature (ECT) is greater than 210°F (99°C) or if A/C high side pressure is above 105 psi (723 kPa) with A/C relay commanded on. The ECM will command high fan speed whenever the (ECT) is greater than 216°F (102°C), A/C high side pressure is above 290 psi (1999 kPa) with A/C relay commanded on or if a circuit fault exists in the ECT sensor circuit. When the relay is commanded off (circuit not grounded), the voltage level at the ECM should be high (ignition voltage). When the relay is commanded on (circuit grounded), the voltage level at the ECM should be low. The ECM cooling fan relay 1 and 2 feedback circuits use a pull-up voltage (2.6-4.6 volts), which allows the ECM to individually differentiate between an open, short to ground or short to voltage. DTC P0480 will set if the ECM detects an open cooling fan relay 1 coil control circuit when the cooling fan relay 1 is commanded off with engine cranking/running.