Schematic Reference : Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: One or both cooling fan motors are inoperative in either high, low, or both speeds.

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, increase and decrease the 3 speed fan through LOW, MEDIUM and HIGH.

Do both fans operate at the proper speeds?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

1. Turn OFF the ignition.
2. Disconnect the cooling fan control module.
3. Disconnect the PCM/ECM.
4. Turn ON the ignition, with the engine OFF.

Test the control circuits of the cooling fan control module for a short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 4

1. Turn Off the ignition.
2. Connect the PCM/ECM.
3. Install a scan tool.
4. Turn ON the ignition, with the engine OFF.
5. Probe the control circuits of the cooling fan control module with a test lamp that is connected to voltage.
6. With a scan tool, command the appropriate fan control circuit ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 5

Go to Step 15

Test the medium speed voltage supply circuit of the cooling fan 1 for short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 6

Test the high/low speed voltage supply circuit of the cooling fan 1 for short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 7

Test the series/parallel circuit of the cooling fan 1 for short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 8

Test the low/high speed voltage supply circuit of the cooling fan 2 for short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 9

Test the medium speed voltage supply circuit of the cooling fan 2 for short to ground, short to voltage, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 10

Test the ground circuit of the cooling fan 2 for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 11

Test the ground circuit of the cooling fan control module for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 12

Test the battery positive voltage circuits of the cooling fan control module for a short to ground, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 13

Test the ignition 3 voltage supply circuit of the cooling fan control module for a short to ground, high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 14

Inspect for poor connections at the cooling fan control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

Inspect for poor connections at the harness connector of the PCM/ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

Replace the cooling fan control module. Refer to Cooling Fan Control Module Replacement .

Did you complete the replacement?

Go to Step 18

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Important: Perform the programming procedure for the PCM/ECM.

Replace the ECM/PCM. Refer to the appropriate procedure:

Did you complete the replacement?

Go to Step 18

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1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK