- Cooling Fan Relay 2 and 3 Control Circuit
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The engine cooling fan system consists of 2 electric cooling fans and 3 fan relays. The cooling fan relays are arranged in a series/parallel (S/P)
configuration. This allows the engine control module (ECM) to operate both fans together at low or high speeds using 2 fan control circuits. The
cooling fans receive positive voltage from the cooling fan relays, which receive battery positive voltage from the underhood fuse block. The
cooling fans are supplied a ground at G100 and G101.
Conditions for Running the DTC
* The system voltage is between 9-18 volts.
* The engine speed is greater than 400 RPM.
* DTCs P0480 and P0481 run continuously when the conditions above are met.
Conditions for Setting the DTC
* The commanded state of the ECM driver and the actual state of the control circuit do not match.
* The condition exists for greater than 5 seconds.
Action Taken When the DTC Sets
DTCs P0480 and P0481 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0480 and P0481 are Type B DTCs.
Diagnostic Aids
* The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the
fan control command parameters on the scan tool to know which fans are being commanded ON by the ECM.
