Chevrolet Trax: Cooling fan inoperative (2H0)

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

Diagnostic Aids

The scan tool cooling fan output control operates as follows:

• Cooling Fan Relay 1 operates the fan at a low speed
• Cooling Fan Relay 2 operates the fan at a high speed

When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

• Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Trax)

Description and Operation

Cooling Fan Description and Operation (2H0)

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify that DTC P0480, P0481, P0691, P0692, P0693, or P0694 is not set.

• If a DTC is set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

• If no DTC is set

3. Verify that the cooling fan operates at low and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool.

• If the cooling fan does not operate at all speeds

Refer to Circuit/System Testing

• If the cooling fan operates at all speeds

4. All OK.

Circuit/System Testing

Inoperative in All Speeds

1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
2. Verify a test lamp illuminates between the ground circuit terminal C and B+.

• If the test lamp does not illuminate

1. Ignition OFF, remove the test lamp.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If the test lamp illuminates

3. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low or High Speed Inoperative

1. Disconnect the following cooling fan relays, ignition ON:

• KR20C Cooling Fan Low Speed Relay
• KR20D Cooling Fan High Speed Relay

2. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below:

• KR20C Cooling Fan Low Speed Relay terminal 30
• KR20D Cooling Fan High Speed Relay terminal 30
• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF, remove the test lamp.
2. Test for less than 2 ohms in the appropriate relay B+ circuit, end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
2. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground:

• KR20C Cooling Fan Low Speed Relay terminal 87
• KR20D Cooling Fan High Speed Relay terminal 87
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary.
• If the test lamp illuminates

3. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON.
4. Command the cooling fan ON at high or low speed as appropriate with a scan tool.
5. Verify a test lamp illuminates between ground and appropriate G10 Cooling Fan Motor circuit terminals listed below:

• G10 Cooling Fan Motor low speed circuit terminal B
• G10 Cooling Fan Motor high speed circuit terminal A
• If the test lamp does not illuminate at each terminal

1. Ignition OFF, remove the test lamp.
2. Disconnect the appropriate relay from the list below:

• KR20C Cooling Fan Low Speed Relay
• KR20D Cooling Fan High Speed Relay

3. Test for less than 2 ohms in the relay controlled output circuit, end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the relay.
• If the test lamp illuminate at each terminal

6. Test or replace the G10 Cooling Fan Motor.

Component Testing

1. Ignition OFF.
2.  Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1.

• If less than 70 ohms or greater than 110 ohms

Replace the cooling fan relay.

• If between 70-110 ohms

4. Test for infinite resistance between following terminals:

• 30/3 and 86/1
• 30/3 and 87/5
• 30/3 and 85/2
• 85/2 and 87/5
• If less than infinite resistance

Replace the cooling fan relay.

• If infinite resistance

5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5.

• If 2 ohms or greater

Replace the cooling fan relay.

• If less than 2 ohms

8. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
• Engine Coolant Fan Replacement (LUJ, LUV), Engine Coolant Fan Replacement (2H0)

ENGINE OVERHEATING

Engine Overheating

Loss of Coolant

Thermostat Diagnosis

Engine Fails To Reach Normal Operating Temperature

COOLING SYSTEM LEAK TESTING

Special Tools

• EN 471 Adapter
• EN 6327 A Cooling System Test Adapter

For equivalent regional Tools, refer to Special Tools.

WARNING: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap.

Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.

WARNING: In order to help avoid being burned, do not remove the radiator cap while the engine and the radiator are hot. Scalding fluid and steam can be blown out under pressure if the cap is removed too soon.

1. Remove the surge tank cap.
2. Check the coolant level.

Fill the coolant level to the COLD mark if necessary.

3. Pull the coolant expansion tank from the bracket in the direction of the battery.

NOTE: Follow manufacturer instructions

4. Attach the coolant system tester with EN 471 adapter and EN 6327 A adapter to the coolant expansion tank.
5. Apply approximately 100 kPa (15 psi) to the cooling system.
6. Check the cooling system for leaks.
7. Remove the cooling system tester.

• Release the pressure
• Remove the cooling system tester with EN 471 adapter

8. Install the surge tank cap.

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