Cruze

DTC P0480 or P0481 - LUJ

The engine cooling fan system is composed of one fan, 3 relays, the engine control module (ECM), and the associated wiring. The fan assembly includes two resistors, which enable the fan to operate at 3 speeds.

Low Speed

In low speed operation, the ECM provides ground from ECM terminal 44 X1. The Cooling Fan Low Speed Relay activates and provides power to the cooling fan motor through cooling fan motor terminal 3 and the internal fan resistor.

Medium Speed

In medium speed operation, the ECM provides ground from ECM terminal 15 X1. The Cooling Fan Medium Speed 1 Relay activates and provides power to the cooling fan motor through cooling fan motor terminal 2 and the internal fan resistor.

High Speed

In high speed operation, the ECM provides ground to ECM terminals 15 X1 and 44 X1. As previously described, power is now provided to both cooling fan terminals 2 and 3. In addition, power and ground are now provided to the coil of the Cooling Fan High Speed Relay. The Cooling Fan High Speed Relay activates and provides power to the cooling fan motor through cooling fan terminal 4.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 2 s.

DTCs P0480 00 and P0481 00 are Type B DTCs.

DTCs P0480 00 and P0481 00 are Type B DTCs.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation : 2.0L Diesel LNP → 1.4L LDD and LUJ → 2.0L Diesel LLW

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, command the appropriate KR20C Cooling Fan Low Speed Relay, KR20A Cooling Fan Medium Speed 1 Relay and KR20D Cooling Fan High Speed Relay ON and OFF with a scan tool. You should hear the relay click when commanded ON and OFF.
2. 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 relays listed below:

•	KR20A Cooling Fan Medium Speed 1 Relay

•	KR20C Cooling Fan Low Speed Relay

•	KR20D Cooling Fan High Speed Relay

2. Ignition ON, verify that a test lamp illuminates between the circuit terminals listed below and ground.

•	KR20A Cooling Fan Medium Speed 1 Relay ignition circuit terminal 86

•	KR20C Cooling Fan Low Speed Relay ignition circuit terminal 86

•	KR20D Cooling Fan High Speed Relay ignition circuit terminal 86

⇒	If the test lamp does not illuminate, replace the X50A Fuse Block - Underbonnet.

3. Verify that a test lamp does not illuminate between the circuit terminals listed below and ground.

•	KR20A Cooling Fan Medium Speed 1 Relay control circuit terminal 85

•	KR20C Cooling Fan Low Speed Relay control circuit terminal 85

⇒	If the test lamp illuminates, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

4. Ignition OFF, disconnect the harness connector X1 at the K20 Engine Control Module. Test for infinite resistance between the relay coil control circuit terminals listed below and ground.

•	KR20A Cooling Fan Medium Speed 1 Relay control terminal 85

•	KR20C Cooling Fan Low Speed Relay control terminal 85

⇒	If less than the specified value, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the X50A Fuse Block - Underhood.

5. Test for less than 5 Ω between control circuit terminals listed below.

•	KR20A Cooling Fan Medium Speed 1 Relay control terminal 85 and K20 Engine Control Module terminal 15 X1.

•	KR20C Cooling Fan Low Speed Relay control terminal 85 and K20 Engine Control Module terminal 44 X1.

•	KR20D Cooling Fan High Speed Relay ignition circuit terminal 85 and K20 Engine Control Module terminal 15 X1.

6. Connect the KR20C Cooling Fan Low Speed Relay and the harness connector X1 at the K20 Engine Control Module.
7. Ignition ON, command the Cooling Fan Relay 1 ON and OFF with a scan tool and verify the DTC does not reset.

⇒	If the DTC resets, test or replace the KR20C Cooling Fan Low Speed Relay and verify the DTC does not reset. If the DTC resets, replace the K20 Engine Control Module.

8. Connect the KR20A Cooling Fan Medium Speed 1 Relay.
9. Command the Cooling Fan Relays 2 and 3 ON and OFF with a scan tool and verify the DTC does not reset.

⇒	If the DTC resets, test or replace the KR20A Cooling Fan Medium Speed 1 Relay and verify the DTC does not reset. If the DTC resets, replace the K20 Engine Control Module.

10. If all circuits test normal, test or replace KR20D Cooling Fan High Speed Relay.

Dynamic Test

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

⇒	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 value, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 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.