Chevrolet Trax: DTC P0480, P0481, P0691, P0692, P0693, OR P0694 (LUJ OR LUV): Cooling fan relay 1/2/3 control circuit

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.

DTC Descriptors

DTC P0480

Cooling Fan Relay 1 Control Circuit

DTC P0481

Cooling Fan Relays 2 and 3 Control Circuit

DTC P0691

Cooling Fan Relay 1 Control Circuit Low Voltage

DTC P0692

Cooling Fan Relay 1 Control Circuit High Voltage

DTC P0693

Cooling Fan Relays 2 and 3 Control Circuit Low Voltage

DTC P0694

Cooling Fan Relays 2 and 3 Control Circuit High Voltage

Diagnostic Fault Information

KR20C Cooling Fan Low Speed Relay

KR20D Cooling Fan High Speed Relay

KR20E Cooling Fan Speed Control Relay

KR20F Cooling Fan Relay

KR20P Cooling Fan Medium Speed Relay

Circuit/System Description

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

Conditions for Running the DTC

LUV or LFF- ECM with 2 Face Mounted Connectors

• The ignition voltage is between 11-32 volts.
• The engine speed is 400 RPM or greater.
• The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
• DTCs P0480 and P0481 run continuously when the conditions above are met.

LUJ- ECM with 3 Face Mounted Connectors

• The ignition voltage is 11 volts or greater.
• The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
• DTCs P0480, P0481, P0691, P0692, P0693, and P0694 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 for greater than 5 seconds.

Action Taken When the DTC Sets

• DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
• DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

Conditions for Clearing the MIL/DTC

• DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
• DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

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 scan tool Cooling Fan Relay Command parameters to know which fans are being commanded ON by the ECM.
• 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 and 3 operates the fan at a medium speed
• Cooling Fan Relay 1, 2 and 3 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 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 (LUJ or LUV)

Electrical Information Reference

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify an audible click is heard or felt from each cooling fan relay when commanding the cooling fan ON and OFF with a scan tool.

• If a click is not heard or felt at each of the relays

Refer to Circuit/System Testing.

• If a click is heard or felt at each of the relays

3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing.

• If the DTC does not set

5. All OK

Circuit/System Testing

1. Ignition OFF, disconnect the cooling fan relays listed below:

• KR20F Cooling Fan Relay
• KR20P Cooling Fan Medium Speed Relay
• KR20D Cooling Fan High Speed Relay

NOTE: The following test must be performed on each of the relay coil ignition circuits.

2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below:

• KR20F Cooling Fan Relay terminal 85/2
• KR20P Cooling Fan Medium Speed Relay terminal 86/1

If the test lamp does not illuminate and the fuse is good.

1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Remove the fuse that supplies ignition voltage to the coil side of the cooling fan relays.
2. Test for less than 2 ohms between the ignition circuit terminal of the appropriate cooling fan relay and the fuse.

• 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, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
2. Test for infinite resistance between the relay coil ignition circuits listed below and ground:

• KR20F Cooling Fan Relay terminal 85/2
• KR20D Cooling Fan High Speed Relay terminal 86/1
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance, test all of the appropriate cooling fan relays for a shorted condition and replace as necessary.
• If the test lamp illuminates

3. Ignition OFF, remove the test lamp, ignition ON.

NOTE:

• The following tests must be performed on all three fan relay control circuits.
• The Red test lead should be connected to the control circuit.

4. Connect a DMM, set on the diode setting, between a control circuit terminal listed below and ground:

• KR20F cooling fan relay terminal 86/1
• KR20P cooling fan medium speed relay terminal 85/2
• KR20D cooling fan high speed relay terminal 85/2

5. Verify the DMM reading is greater than 2.5 V or displays O.L.

• If 2.5 V or less

1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Disconnect the harness connector X1 at the K20 Engine Control Module.
2. Test for infinite resistance between the appropriate relay coil control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 Engine Control Module.
• If greater than 2.5 V or displays O.L.

NOTE: The following test must be performed on all three fan relay circuits.

6. Verify the DMM reading is less than 1 V when commanding the Cooling Fan Relays ON with a scan tool.

• If 1 V or greater

1. Ignition OFF, disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the appropriate cooling fan relay control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V.

3. Ignition OFF.
4. Test for less than 2 ohms in the appropriate cooling fan relay control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If less than 1 V

7. Test or replace the appropriate cooling fan relay.

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 or greater than the specified range

Replace the cooling fan relay.

• If within the specified range

4. Test for infinite resistance between the 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 diagnostic procedure.

• Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
• Control Module References for ECM replacement, setup, and programming

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