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Engine Cooling System: Overview Oldsmobile Bravada III

Cooling System (Mechanical) ~1095 words

Test Description

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

  1. 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
  2. 3: Determine if the Instrument Cluster or Powertrain Control Modules have set DTCs which may affect Engine Cooling operation are present.
  3. 4: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
  4. 5: If DTC P1484 or P0495 is set along with DTC P0113 and the weather conditions are cold, the cooling fan codes may be false.
StepActionYesNo
1Install a scan tool. Does the scan tool power up?Go to Step 2Go to SCAN TOOL DOES NOT POWER UP in Data Link Communications
2Turn ON the ignition, with the engine OFF. Attempt to establish communication with the powertrain control module. Does the scan tool communicate with the powertrain control module?Go to Step 3Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 Device (W/O Immobilizer) in Data Link Communications
3Select the powertrain control module display DTCs function on the scan tool. Does the scan tool display any DTCs?Go to Step 4Go to Symptoms - Engine Cooling .
4Does the scan tool display any DTCs which begin with a "U"?Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 Device (W/O Immobilizer) in Data Link CommunicationsGo to Step 5
5Does the scan tool display DTC P0112 or P0113?Go to DIAGNOSTIC TESTS .Go to Diagnostic Trouble Code (DTC) List

Diagnostic System Check - Engine Cooling

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

  1. 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, then the answer is No.
  2. 3: The cooling fan noise should increase as the cooling fan engages. It can take up to 2 minutes for full cooling fan engagement. If cooling fan is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, then answer Yes.
  3. 4: In the previous step the cooling fan was fully engaged. This step tests to ensure that the cooling fan will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan and a disengaged cooling fan. The cooling fan is completely disengaged when the excessive fan noise is not heard.
  4. 5: Tests the ability of the PCM to control the cooling fan speed. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
  5. 6: Disconnecting the cooling fan and running the engine ensure that the cooling fan is not engaged. When rotating the cooling fan it should spin freely. If not then the cooling fan will not disengage.
StepActionYesNo
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views
1Did you perform the Engine Cooling Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Engine Cooling
2With a scan tool, observe the Powertrain DTC list. Start the engine. Operate the vehicle within the Conditions for Running in the DTC. Does the scan tool indicate the DTC Failed this ignition cycle?Go to Step 5Go to Step 3
3IMPORTANT: DTC P1482, for 4.2l (LL8), will set when the cooling fan relay is disconnected. Turn OFF the ignition. Disconnect the coolant fan relay. Connect a 10 amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan and the ignition 3 voltage circuit of the cooling fan relay. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan engage?Go to Step 4Go to Step 5
4IMPORTANT: Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan will not correct the condition. Turn OFF the ignition. Remove the 10 amp fused jumper wire. Install cooling fan relay. Disconnect the cooling fan connector. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan disengage?Go to Step 5Go to Step 11
5Install a scan tool. Start the engine. With a scan tool, observe the Fan Speed parameter in the PCM ENG 2 data list. Operate the engine at 2000 RPM for 2 minutes. Is the cooling fan speed less than 1600 RPM?Go to Diagnostic AidsGo to Step 6
6Turn OFF the ignition. Disconnect the cooling fan connector. Start the engine. Run the engine at 2000 RPM for 2 minutes. Turn OFF the engine. Rotate the cooling fan 2 revolutions. Does the cooling fan rotate freely?Go to Step 7Go to Step 13
7Disconnect the harness connector at the shroud. Turn ON the ignition. Connect a test lamp between the cooling fan clutch supply voltage circuit of the cooling fan and ground. Does the test lamp illuminate?Go to Step 8Go to Step 11
8Disconnect the cooling fan relay. Does the test lamp remain illuminated?Go to Step 9Go to Step 10
9Repair the cooling fan clutch supply voltage circuit of the cooling fan for a short to voltage. Refer to WIRING REPAIRS in Wiring Systems. Did you complete the repair?Go to Step 14
10Inspect for poor connections at the cooling fan relay. 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 14Go to Step 12
11Inspect for poor connections at the cooling fan. 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 14Go to Step 13
12Replace the cooling fan relay. Did you complete the replacement?Go to Step 14
13Replace the cooling fan. Refer to Fan Clutch Replacement . Did you complete the replacement?Go to Step 14
14Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running in the DTC. Does the DTC reset?Go to Step 2System OK
IMPORTANT
DTC P1482, for 4.2l (LL8), will set when the cooling fan relay is disconnected.
IMPORTANT
Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan will not correct the condition.

DTC P0495

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

  1. 2: Tests that the PCM receives a cooling fan speed signal through the cooling fan speed signal circuit. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
  2. 3: Tests for the proper operation of the clutch hall effect sensor.
  3. 4: Tests for the proper operation of the 5-volt reference circuit and of the low reference circuit of the cooling fan.
StepActionValuesYesNo
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views
1Did you perform the Engine Cooling Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Engine Cooling
2Install a scan tool. Start the engine. With the scan tool, observe the Fan Speed parameter in the PCM ENG 3 data list. Does the scan tool indicate that the Fan Speed parameter is within the specified range?550-800 RPMGo to Diagnostic AidsGo to Step 3
3Turn OFF the ignition. Disconnect the cooling fan clutch harness connector at the shroud. Connect a jumper wire between each of the following circuits: The 5-volt reference circuit The cooling fan speed signal circuit The low reference circuit Connect a digital multimeter (DMM) to the cooling fan speed signal circuit and ground. Turn ON the ignition with the engine OFF. Manually rotate the cooling fan. Does the DMM voltage change?0-5 VGo to Step 10Go to Step 4
4Disconnect the jumper wires. Measure the voltage between the 5-volt reference circuit and the low reference circuit of the cooling fan. Is the voltage measurement near than the specified value?5 VGo to Step 5Go to Step 7
5Turn OFF the ignition. Probe the low reference circuit of the cooling fan clutch with a test lamp connected to battery positive voltage. Does the test lamp illuminate?Go to Step 6Go to Step 9
6Test the 5-volt reference circuit of the cooling fan clutch for a high resistance, or for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 7
7Test the cooling fan speed signal circuit of the cooling fan clutch for a short to ground, for a high resistance, or for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 8
8Test the cooling fan speed signal circuit of the cooling fan clutch for a short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 11
9Disconnect the PCM. Test the low reference circuit of the cooling fan for a high resistance or for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 12
10Disconnect the jumper wires. Test the cooling fan speed signal circuit of the cooling fan clutch for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 12
11Inspect for a poor connection at the harness connector of the cooling fan clutch. 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 15Go to Step 13
12Inspect for poor connections at the harness connector of the PCM. 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 15Go to Step 14
13Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement?Go to Step 15
14IMPORTANT: Program the PCM. Replace the PCM. Refer to POWERTRAIN CONTROL MODULE .Did you complete the replacement?Go to Step 15
15Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running in the DTC. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Program the PCM.

DTC P1481

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

  1. 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, then the answer is No.
  2. 3: The cooling fan noise should increase as the cooling fan clutch engages. It can take up to 2 minutes for full cooling fan clutch engagement. If cooling fan clutch is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, then answer Yes.
  3. 4: In the previous step the cooling fan clutch was fully engaged. This step tests to ensure that the cooling fan clutch will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan clutch and a disengaged cooling fan clutch. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
  4. 5: Tests for the ability of the PCM to control cooling fan clutch speed. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
  5. 6: Verifies the ignition 1 voltage circuit of the cooling fan relay.
StepActionValuesYesNo
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views
1Did you perform the Engine Cooling Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Engine Cooling
2With a scan tool, observe the Powertrain DTC list. Start the engine. Operate the vehicle within the Conditions for Running in the DTC. Does the scan tool indicate the DTC Failed this ignition cycle?Go to Step 5Go to Step 3
3IMPORTANT: DTC P1482, for 4.2l (LL8) will set when the cooling fan relay is disconnected. Turn OFF the ignition. Disconnect the coolant fan relay. Connect a 10 amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan and the ignition 3 voltage circuit of the cooling fan relay. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan engage?Go to Step 4Go to Step 5
4IMPORTANT: Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan will not correct the condition. Turn OFF the ignition. Remove the 10 amp fused jumper wire. Install cooling fan relay. Disconnect the cooling fan clutch connector. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan clutch disengage?Go to Step 5Go to Step 17
5Install a scan tool. Start the engine. Observe the Fan Speed parameter in the powertrain control module Output Controls. With a scan tool, command the fan speed to increase. Does the Fan Speed increase?Go to Diagnostic AidsGo to Step 6
6Turn OFF the ignition. Disconnect the cooling fan relay. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the cooling fan relay with a test lamp connected a good ground. Does the test lamp illuminate?Go to Step 7Go to Step 11
7Test the cooling fan clutch control circuit of the cooling fan relay for a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 19Go to Step 8
8Test the cooling fan clutch control circuit of the cooling fan relay for a short to ground. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 19Go to Step 9
9Connect a test lamp to the cooling fan clutch control circuit of the cooling fan relay and ground. Connect a digital multimeter (DMM) to the test lamp probe and ground. Set the DMM to A/C range and select frequency. Start the engine. Verify that the Fan Control is commanded to 0%. Is the frequency less than the specified value?OLGo to Step 14Go to Step 10
10Command the Fan Control to 100%. Does the frequency fluctuate?Go to Step 13Go to Step 14
11Inspect the Eng Fan fuse. Is the fuse open?Go to Step 12Go to Step 15
12Test the cooling fan clutch control circuit of the cooling fan relay for a short to ground. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 19Go to Step 15
13Inspect for poor connections at the cooling fan relay. 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 19Go to Step 16
14Inspect for poor connections at the harness connector of the PCM. 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 19Go to Step 18
15Repair the ignition 1 voltage circuit of the cooling fan relay. Refer to WIRING REPAIRS in Wiring Systems. Did you complete the repair?Go to Step 19
16Replace the cooling fan relay. Did you complete the replacement?Go to Step 19
17Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement?Go to Step 19
18IMPORTANT: Perform the programming procedure for the PCM. Replace the PCM. Refer to POWERTRAIN CONTROL MODULE .Did you complete the replacement?Go to Step 19
19Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
DTC P1482, for 4.2l (LL8) will set when the cooling fan relay is disconnected.
IMPORTANT
Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan will not correct the condition.
IMPORTANT
Perform the programming procedure for the PCM.

DTC P1482

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

  1. 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, then the answer is No.
  2. 3: The cooling fan noise should increase as the cooling fan clutch engages. It can take up to 2 minutes for full cooling fan clutch engagement. If cooling fan clutch is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, then answer Yes.
  3. 4: In the previous step the cooling fan clutch was fully engaged. This step tests to ensure that the cooling fan clutch will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan clutch and a disengaged cooling fan clutch. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
  4. 5: Tests the PCM's ability to control the cooling fan. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
  5. 6: Inspect for a mechanical condition which causes the DTC to set.
  6. 7: Tests for voltage on the cooling fan clutch supply voltage circuit of the cooling fan clutch. The cooling fan clutch connector is a seal connector. You must use jumper wires for testing or damage to wiring or connector could happen.
  7. 8: Tests the cooling fan relay for a PWM signal on the cooling fan clutch supply voltage circuit of the cooling fan clutch.
StepActionValuesYesNo
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views
1Did you perform the Engine Cooling Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Engine Cooling
2With a scan tool, observe the Powertrain DTC list. Start the engine. Operate the vehicle within the Conditions for Running in the DTC. Does the scan tool indicate the DTC Failed this ignition cycle?Go to Step 5Go to Step 3
3IMPORTANT: DTC P1482, for 4.2l (LL8) will set when the cooling fan relay is disconnected. Turn OFF the ignition. Disconnect the coolant fan relay. Connect a 10 amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan and the ignition 3 voltage circuit of the cooling fan relay. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan engage?Go to Step 4Go to Step 5
4IMPORTANT: Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan clutch will not correct the condition. Turn OFF the ignition. Remove the 10 amp fused jumper wire. Install cooling fan relay. Disconnect the cooling fan clutch connector. Start the engine. Raise engine speed to 2000 RPM for 2 minutes. Does the cooling fan clutch disengage?Go to Step 5Go to Step 18
5Install a scan tool. Start the engine. With a scan tool, observe the Fan Speed and the Desired Fan Speed parameters in the powertrain control module Output Controls. Command the cooling fan clutch to 100%. Operate the engine at 2000 RPM for 2 minutes. Is the Desired Fan Speed within the specified speed of the Fan Speed?1000 RPMGo to Diagnostic AidsGo to Step 6
6Turn OFF the ignition. Inspect the cooling fan and the drive belt for the following conditions: A cracked drive belt A loose or a worn drive belt A misrouted drive belt Oil leaks at the cooling fan clutch A free-spinning cooling fan A seized cooling fan clutch A broken cooling fan If the above conditions exist, refer to one of the following procedures: Cooling Fan and Shroud Replacement DRIVE BELT EXCESSIVE WEAR DIAGNOSIS in Engine Mechanical-4.2L DRIVE BELT TENSIONER DIAGNOSIS in Engine Mechanical-4.2L Did you find and correct the condition?Go to Step 20Go to Step 7
7Disconnect the cooling fan clutch connector at the fan shroud. Connect a jumper wire between each of the cooling fan clutch circuits. Connect a digital multimeter (DMM) between the clutch supply voltage circuit of the cooling fan clutch and ground. Start the engine. Command the Fan Control to 0%. Does the voltage measure greater than the specified value?0.16 VGo to Step 10Go to Step 8
8Command the fan control to 100%. Does the voltage fluctuate?Go to Step 11Go to Step 9
9Turn OFF the ignition. Disconnect the cooling fan relay. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the cooling fan relay with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 12Go to Step 17
10Disconnect the cooling fan relay. Does the voltage measure greater than the specified value?0.16 VGo to Step 14Go to Step 11
11Test the cooling fan clutch ground for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 16
12Test the ground circuit of the cooling fan relay for an open or a high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 13
13Test the clutch supply voltage circuit of the cooling fan clutch for an open or a short to ground. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 15
14Test the clutch supply voltage circuit of the cooling fan clutch for a short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 20
15Inspect for poor connections at the cooling fan relay. 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 20Go to Step 19
16Inspect for poor connections at the harness connector of the cooling fan clutch. 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 20Go to Step 18
17Repair the ignition 1 voltage circuit of the cooling fan relay. Refer to WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?Go to Step 20
18Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement?Go to Step 20
19Replace the cooling fan relay. Did you complete the replacement?Go to Step 20
20IMPORTANT: Follow this procedure in order to clear DTC P1484 after making a repair. Use the Clear DTC Information function of the scan tool. Perform an ignition key cycle. Operate the vehicle within the Conditions for Running in the DTC. Does the DTC reset?Go to Step 2System OK
IMPORTANT
DTC P1482, for 4.2l (LL8) will set when the cooling fan relay is disconnected.
IMPORTANT
Continuously excessive fan noise is due to the PCM commanding the cooling fan to 100% engaged or a mechanical failure. If the fan noise decreases during this step, then this DTC is due to an electrical malfunction. Replacing the cooling fan clutch will not correct the condition.
IMPORTANT
Follow this procedure in order to clear DTC P1484 after making a repair.

DTC P1484

Symptoms - Engine Cooling

IMPORTANTReview the system operation in order to familiarize yourself with the system functions. Refer to Cooling System Description and Operation .

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

  1. 2: There should be no binding or increased resistance as the cooling fan clutch is rotated.
  2. 4: The cooling fan noise should increase as the cooling fan clutch engages. It can take up to 2 minutes for full cooling fan clutch engagement. If cooling fan clutch is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, then answer Yes.
  3. 5: In the previous step the cooling fan clutch was fully engaged. This step tests to ensure that the cooling fan clutch will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan clutch and a disengaged cooling fan. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
  4. 6: This step clears DTC that were set during previous steps. Test driving the vehicle will attempt to set DTC not previous found in the Engine Cooling Diagnostic Check. If no DTC is set the condition is normal operation of the cooling fan.
StepActionYesNo
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views DEFINITION: The cooling fan clutch has excessive fan noise.
1Did you perform the Engine Cooling Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Engine Cooling .
2Rotate the cooling fan 3 complete revolutions? Is the resistance of the cooling fan clutch even through out each rotation?Go to Step 4Go to Step 3
3Inspect the cooling fan clutch for proper installation. Refer to Fan Clutch Replacement . Did you find and correct the condition?Go to Step 9Go to Step 7
4IMPORTANT: DTC P1482, for 4.2L (LL8), and P0480, for 5.3L (LM4), will set when the cooling fan relay is disconnected. Turn OFF the ignition. Disconnect the coolant fan relay. Connect a 10-amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan and the ignition 3 voltage circuit of the cooling fan relay. Start the engine. Raise engine speed to 2,000 RPM for 2 minutes. Does the cooling fan clutch engage?Go to Step 5Go to Step 7
5IMPORTANT: Continuous excessive fan noise is due to a mechanical failure. If the fan noise decreases during this step, then there is an electrical malfunction. Replacing the cooling fan clutch will not correct the condition. Turn OFF the ignition. Remove the 10-amp fused jumper wire. Install cooling fan relay. Disconnect the cooling fan clutch connector. Start the engine. Raise engine speed to 2,000 RPM for 2 minutes. Does the cooling fan disengage?System OKGo to Step 6
6Turn OFF the ignition. Connect the cooling fan clutch connector. Turn ON the ignition, with the engine OFF. With a scan tool, clear all DTC. Start the engine. Test drive vehicle. With a scan tool, observe the DTC list. Does the scan tool display any cooling system DTC?Go to Diagnostic Trouble Code (DTC) ListSystem OK
7Inspect for poor connections at the harness connector of the cooling fan clutch. 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 9Go to Step 8
8Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement?Go to Step 9
9Operate the system in order to verify the repair. Did you correct the condition?System OKGo to Step 3
IMPORTANT
DTC P1482, for 4.2L (LL8), and P0480, for 5.3L (LM4), will set when the cooling fan relay is disconnected.
IMPORTANT
Continuous excessive fan noise is due to a mechanical failure. If the fan noise decreases during this step, then there is an electrical malfunction. Replacing the cooling fan clutch will not correct the condition.

Excessive Fan Noise

More articles — Engine Cooling System