Cruze

DTC P0480, P0481, or P0482

The engine control module (ECM) commands the fans ON in either high speed or low speed, depending on cooling requirements. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.

In low speed operation, the ECM applies ground to the coil side of the low speed fan relay. This energizes the coil and applies voltage directly to the main cooling fan through the switch side of the low relay. The main fan is connected in series to the auxiliary cooling fan through the de-energized series/parallel fan control relay. The series circuit operates both fans at low speed.

In high speed operation, the ECM applies a ground to the coil side of the low speed fan relay, the fan control relay, and the high speed fan relay. When energized, the high speed fan relay applies voltage directly to the auxiliary cooling fan through the switch side of the relay. Simultaneously, the low speed fan relay and the fan control relay provide ignition voltage and a direct path to ground for the main cooling fan. With both fans connected in a parallel circuit, each fan receives full voltage and operates at high speed.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 1 s.

DTCs P0480, P0481, and P0482 are Type C DTCs.

DTCs P0480, P0481, and P0482 are Type C DTCs.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, command the cooling fan relay 1 ON and OFF with a scan tool. You should hear the KR20E Cooling Fan Speed Control Relay and the KR20F Cooling Fan Relay click when commanded ON and OFF.
2. Command the cooling fan relay 2 ON and OFF with a scan tool. You should hear the KR20A Cooling Fan Medium Speed 1 Relay click when commanded ON and OFF.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the KR20A Cooling Fan Medium Speed 1 Relay, KR20E Cooling Fan Speed Control Relay and the KR20F Cooling Fan Relay.
2. Ignition ON, verify that a test lamp illuminates between all relay coil ignition circuit terminals 86 and ground:

⇒	If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.

3. Connect a test lamp between the KR20F Cooling Fan Relay coil control circuit terminal 85 and B+.
4. Command the cooling fan relay 1 ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

5. Ignition OFF, connect the KR20F Cooling Fan Relay.
6. Ignition ON, connect a test lamp between the KR20E Cooling Fan Speed Control Relay coil control circuit terminal 85 and B+.
7. Command the cooling fan relay 1 ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

8. Connect a test lamp between the KR20A Cooling Fan Medium Speed 1 Relay coil control circuit terminal 85 and B+.
9. Command the cooling fan relay 2 ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

10. If all circuits test normal, test or replace the appropriate relay.

Static Test

1. Ignition OFF, disconnect the appropriate cooling fan relay.
2. Test for 70-110 Ω between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified range, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 86 and B+. Install a jumper wire between relay terminal 85 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.