GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Cooling Fan Always On

Diagnostic Aids

Check for the following conditions:

If the vehicle coolant temperature reaches approximately 113°C (235°F) with the ignition OFF the afterboil will allow the cooling fan to operate for a maximum of 2 minutes. For a description and operation of the cooling fan go to Cooling System Description and Operation .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Determines if the failure is present or intermittent.

    2.

  2. Determines if the cooling fan processor or the ECM is defective.

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition with the engine OFF.
  2. Turn OFF the HVAC controls.

Does the engine cooling fan operate?

Go to Step 3

Go to Diagnostic Aids

3

Turn OFF the ignition.

Does the cooling fan still operate?

Go to Step 4

Go to Step 5

4

Replace the cooling fan speed control processor. Refer to Cooling Fan and Shroud Replacement .

Did you complete the replacement?

Go to Step 6

--

5

Important: Perform the set up procedure for the ECM.

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls.

Did you complete the replacement?

Go to Step 6

--

6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2