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Cooling Fan Inoperative - LNP

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.

Diagnostic Fault Information

Cooling Fan Low Speed Relay

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Relay Coil Ignition

P0691 00

P0691 00

P0480 00

-

-

Relay Switch B+

1

1

1

-

-

Relay Coil Control

P0691 00

P0691 00

P0480 00

P0692 00

-

Relay Output Control

1

1

1

2

-

1. Fan Inoperative Without a DTC.

2. Fan Always ON Without a DTC.

Cooling Fan Left Medium Speed Relay

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Relay Coil Ignition

P0693 00

P0693 00

P0481 00

-

-

Relay Switch B+

1

1

1

-

-

Relay Coil Control

P0693 00

P0693 00

P0481 00

P0694 00

-

Relay Output Control

1

1

1

2

-

1. Fan Inoperative Without a DTC.

2. Fan Always ON Without a DTC.

Cooling Fan Right Medium Speed Relay

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Relay Coil Ignition

P0693 00

P0693 00

P0481 00

-

-

Relay Switch B+

1

1

1

-

-

Relay Coil Control

P0693 00

P0693 00

P0481 00

P0694 00

-

Relay Output Control

1

1

1

2

-

1. Fan Inoperative Without a DTC.

2. Fan Always ON Without a DTC.

Cooling Fan Speed Control 2 Relay

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Relay Coil Ignition

P0693 00

P0693 00

P0481 00

-

-

Relay Switch B+

1

1

1

-

-

Relay Coil Control

P0693 00

P0693 00

P0481 00

P0694 00

-

Relay Output Control

1

1

1

2

-

1. Fan Inoperative Without a DTC.

2. Fan Always ON Without a DTC.

Cooling Fan High Speed Relay

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Relay Coil Ignition

P0695 00

P0695 00

P0482 00

-

-

Relay Switch B+

1

1

1

-

-

Relay Coil Control

P0695 00

P0695 00

P0482 00

P0696 00

-

Relay Output Control

1

1

1

2

-

1. Fan Inoperative Without a DTC.

2. Fan Always ON Without a DTC.

Circuit/System Description

The engine control module (ECM) commands the fans ON in either high speed, medium speed, or low speed, depending on cooling requirements.

Low Speed

In low speed operation, the ECM commands the low speed fan relay on. This energises the relay coil. The low speed cooling fan relay supply power directly to the right cooling fan motor. The earth circuit of the right cooling fan motor is connected to the left cooling fan motor through the cooling fan speed control 2 relay. Both cooling fan motors are running slowly.

Medium Speed

In medium speed operation, the ECM applies earth to the coil side of the cooling fan left medium speed relay, the cooling fan right medium speed relay and the cooling fan speed control 2 relay. This energizes the relay coils. The medium speed cooling fan relays supply power to the left cooling fan motor and the right cooling fan motor through internal fan resistors. The cooling fan speed control 2 relay supplies earth to the right cooling fan motor. Both cooling fan motors are running with medium speed.

High Speed

In high speed operation, the ECM applies ground to the coil side of the cooling fan high speed relay. When energised, the high speed relay applies voltage directly to the left cooling fan motor. The left cooling fan motor is running with maximum speed.

Reference Information

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 → LDE, LLU, LXV, 2H0 LUW and LFH

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, verify that DTCs P0480, P0481, P0482, P0691, P0692, P0693, P0694, P0695, or P0696 are not set.
    2. ⇒If any of the above DTCs are set, refer to DTC P0480-P0482 or P0691-P0696 : LNP or LNQ .
  2. Verify that DTCs P0116, P0117, P0118, or P0119 are not set.
    3. ⇒If any of the above DTCs are set, refer to DTC P0116-P0119 : LNP or LNQ .
  3. Command the cooling fan relay 1 ON and OFF with a scan tool. The cooling fans should operate on low speed when commanded ON, and turn OFF when commanded OFF.
    4. ⇒If the cooling fans are not running, refer to Low Speed Circuit Malfunction.
  4. Command the cooling fan relay 2 ON and OFF with a scan tool. The cooling fans should operate on medium speed when commanded ON, and turn OFF when commanded OFF.
    5. ⇒If the cooling fans are not running, refer to Medium Speed Circuit Malfunction.
  5. Command the cooling fan relay 3 ON and OFF with a scan tool. The left cooling fan should operate on maximum speed when commanded ON, and turn OFF when commanded OFF.
    6. ⇒If the left cooling fan is not running, refer to High Speed Circuit Malfunction.

Circuit/System Testing

Low Speed Circuit Malfunction

  1. Ignition OFF, disconnect the KR20C Cooling Fan Low Speed Relay.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 87 and earth.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  3. Ignition OFF, disconnect the harness connector at the G10L Cooling Fan Motor - Left.
  4. Verify that a test lamp illuminates between the earth circuit terminal C and B+.
    5. ⇒If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Connect the harness connector at the G10L Cooling Fan Motor - Left and disconnect the KR20L Cooling Fan Speed Control 2 Relay.
  6. Install a 20 A fused jumper wire between the controlled output circuit terminal 87A at the KR20L Cooling Fan Speed Control 2 Relay and B+. Verify that the G10L Cooling Fan Motor - Left is running.
    7. ⇒If the G10L Cooling Fan Motor - Left is not running, test the controlled output circuit for an open/high resistance. If the circuit tests normal, replace the G10L Cooling Fan Motor - Left.
  7. Connect the KR20C Cooling Fan Low Speed Relay and the KR20L Cooling Fan Speed Control 2 Relay. Disconnect the harness connector at the G10R Cooling Fan Motor - Right.
  8. Connect a test lamp illuminates between the control circuit terminal A at the G10R Cooling Fan Motor - Right and earth.
  9. Ignition ON, command the cooling fan relay 1 ON with a scan tool. Verify that the test lamp illuminates.
    10. ⇒If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the KR20C Cooling Fan Low Speed Relay.
  10. Install a 20 A fused jumper wire between the control circuit terminal A and the earth circuit terminal C at the G10R Cooling Fan Motor - Right.
  11. Command the cooling fan relay 1 ON with a scan tool. Verify that the G10L Cooling Fan Motor - Left is running.
    12. ⇒If the G10L Cooling Fan Motor - Left is not running, test the earth circuit for an open/high resistance. If the circuit tests normal, replace the KR20L Cooling Fan Speed Control 2 Relay.
  12. If all circuits test normal, replace the G10R Cooling Fan Motor - Right.

Medium Speed Circuit Malfunction

  1. Ignition OFF, disconnect the KR20M Cooling Fan Left Medium Speed Relay and the KR20N Cooling Fan Right Medium Speed Relay.
  2. Ignition ON, verify that a test lamp illuminates between both B+ circuit terminals 30 and earth.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  3. Connect the KR20M Cooling Fan Left Medium Speed Relay and the KR20N Cooling Fan Right Medium Speed Relay.
  4. Command the cooling fan relay 2 ON with a scan tool. Verify that the G10L Cooling Fan Motor - Left is running.
    5. ⇒If the G10L Cooling Fan Motor - Left is not running, test the control circuit for an open/high resistance. If the circuit tests normal, replace the KR20M Cooling Fan Left Medium Speed Relay.
  5. Ignition OFF, disconnect the harness connector at the G10R Cooling Fan Motor - Right.
  6. Connect a test lamp between the control circuit terminal B and earth.
  7. Ignition ON, command the cooling fan relay 2 ON with a scan tool. Verify that the test lamp illuminates.
    8. ⇒If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the KR20N Cooling Fan Right Medium Speed Relay.
  8. Ignition OFF, disconnect the KR20L Cooling Fan Speed Control 2 Relay and connect the harness connector at the G10R Cooling Fan Motor - Right.
  9. Install a 20 A fused jumper wire between the control circuit terminal 30 and the earth circuit terminal 87 at the KR20L Cooling Fan Speed Control 2 Relay.
  10. Ignition ON, command the cooling fan relay 2 ON with a scan tool. Verify that the G10R Cooling Fan Motor - Right is running.
    11. ⇒If the G10R Cooling Fan Motor - Right is not running, test the earth circuit for an open/high resistance. If the circuit tests normal, replace the G10R Cooling Fan Motor - Right.
  11. If all circuits test normal, replace the KR20L Cooling Fan Speed Control 2 Relay.

High Speed Circuit Malfunction

  1. Ignition OFF, disconnect the KR20D Cooling Fan High Speed Relay.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminals 87 and earth.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  3. Install a 30 A fused jumper wire between the control circuit terminal 30 and the B+ circuit terminal 87. Verify that the G10L Cooling Fan Motor - Left is running.
    4. ⇒If the G10L Cooling Fan Motor - Left is not running, test the control circuit for an open/high resistance. If the circuit tests normal, replace the G10L Cooling Fan Motor - Left.
  4. If all circuits test normal, replace the KR20D Cooling Fan High Speed Relay.

Component Testing

Static Test

  1. Ignition OFF, disconnect the cooling fan relay.
  2. Test for 70-110 Ω between terminals 85 and 86.
  3. Install the fan control relay. Verify both fans activate at low speed.
    4. ⇒If both fans do not activate, test the relay controlled output circuit terminal 87A of the fan control relay for a short to ground or an open/high resistance.
    • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
         ⇒If not the specified range, replace the relay.
  4. Test for less than 2 Ω between the relay terminals 30 and 87A.
    5. ⇒If greater than the specified range, replace the relay.
  5. Install a 20 A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between the relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.
    6. ⇒If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Fan Replacement : 1.8L 2H0 - Manual Transmission → 1.8L 2H0 - Automatic Transmission → 2.0L Diesel LNP

   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved