Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests for the ability of the PCM to control fan speed. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
- 3: This step verifies the ignition 1 voltage circuit of the cooling fan relay.
| Step | Action | Values | 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 | Install a scan tool. Start the engine. Observe the Fan Speed parameter in the powertrain control module (PCM) Output Controls. With a scan tool, command the fan speed to increase. Does the Fan Speed parameter increase? | Go to Diagnostic Aids | Go to Step 3 | |
| 3 | Turn 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 4 | Go to Step 10 | |
| 4 | Test 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 13 | Go to Step 5 | |
| 5 | Test 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 13 | Go to Step 6 | |
| 6 | Connect a test lamp to the cooling fan clutch control circuit of the cooling fan relay and ground. Connect a 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 percent. Is the frequency less than the specified value? | OL | Go to Step 9 | Go to Step 7 |
| 7 | Command the Fan Control to 100 percent. Does the frequency fluctuate? | Go to Step 8 | Go to Step 9 | |
| 8 | Inspect 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 13 | Go to Step 11 | |
| 9 | Inspect 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 13 | Go to Step 12 | |
| 10 | Repair 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 13 | ||
| 11 | Replace the cooling fan relay. Did you complete the replacement? | Go to Step 13 | ||
| 12 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | ||
| 13 | Use 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 2 | System OK | |
DTC P0480
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, then the answer is No.
- 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.
- 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. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
- 5: This step tests the PCM's ability to control the cooling fan clutch. If answer to question is Yes, ensure to refer to all Diagnostic Aids.
- 6: This step inspects for a mechanical condition which causes the DTC to set.
- 7: This step tests for voltage on the cooling fan clutch supply voltage circuit of the cooling fan clutch. The cooling fan connector is a seal connector. You must use jumper wires for testing or damage to wiring or connector could happen.
- 8: This step tests the cooling fan relay for a PWM signal on the cooling fan clutch supply voltage circuit of the cooling fan.
| Step | Action | Values | 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 | With 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 5 | Go to Step 3 | |
| 3 | IMPORTANT: 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 4 | Go to Step 5 | |
| 4 | IMPORTANT: Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan clutch to 100 percent 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 2,000 RPM for 2 minutes. Does the cooling fan clutch disengage? | Go to Step 5 | Go to Step 18 | |
| 5 | Install 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 percent. Operate the engine at 2,000 RPM for 2 minutes. Is the Desired Fan Speed within the specified speed of the Fan Speed? | 4.2L (LL8) 1,000 RPM 5.3L (LM4) 2,000 RPM | Go to Diagnostic Aids | Go to Step 6 |
| 6 | Turn 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 Cooling Fan and Shroud Replacement . Did you find and correct the condition? | Go to Step 20 | Go to Step 7 | |
| 7 | Disconnect the cooling fan clutch connector at the fan shroud. Connect a jumper wire between each of the cooling fan clutch circuits. Connect a DMM between the clutch supply voltage circuit of the cooling fan clutch and ground. Start the engine. Command the Fan Control to 0 percent. Does the voltage measure greater than the specified value? | 0.16 V | Go to Step 10 | Go to Step 8 |
| 8 | Command the Fan Control to 100 percent. Does the voltage fluctuate? | Go to Step 11 | Go to Step 9 | |
| 9 | Turn 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 12 | Go to Step 17 | |
| 10 | Disconnect the cooling fan relay. Does the voltage measure greater than the specified value? | 0.16 V | Go to Step 14 | Go to Step 11 |
| 11 | Test the cooling fan ground for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 16 | |
| 12 | Test the ground circuit of the cooling fan relay for an open or a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 13 | |
| 13 | Test the clutch supply voltage circuit of the cooling fan clutch for an open or a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 15 | |
| 14 | Test the clutch supply voltage circuit of the cooling fan clutch for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | ||
| 15 | Inspect for poor connections at the cooling fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 16 | Inspect for poor connections at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 18 | |
| 17 | Repair 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 | ||
| 18 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 20 | ||
| 19 | Replace the cooling fan relay. Did you complete the replacement? | Go to Step 20 | ||
| 20 | IMPORTANT: Follow this procedure in order to clear DTC P0483 or DTC P0493 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 2 | System OK | |
| IMPORTANT |
|---|
| P0480, for 5.3L (LM4), will set when the cooling fan relay is disconnected. |
| IMPORTANT |
|---|
| Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan clutch to 100 percent 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 P0483 or DTC P0493 after making a repair. |
DTC P0483 or P0493
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, the answer is No.
- 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, answer Yes.
- 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.
- 5: Tests the ability of the PCM to control the cooling fan speed. If answer to question is Yes, refer to all Diagnostic Aids.
- 6: Disconnecting the cooling fan clutch and running the engine ensure that the cooling fan clutch is not engaged. When rotating the cooling fan clutch it should spin freely. If not, the cooling fan clutch will not disengage.
| 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 | With 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 5 | Go to Step 3 |
| 3 | IMPORTANT: 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 cooling fan relay. Connect a 10-amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan clutch 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 4 | Go to Step 5 |
| 4 | IMPORTANT: Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan clutch to 100 percent 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 2,000 RPM for 2 minutes. Does the cooling fan clutch disengage? | Go to Step 5 | Go to Step 11 |
| 5 | Install 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 2,000 RPM for 2 minutes. Is the Fan Speed parameter less than 1600 RPM? | Go to Diagnostic Aids | Go to Step 6 |
| 6 | Turn OFF the ignition. Disconnect the cooling fan clutch connector. Start the engine. Run the engine at 2,000 RPM for 2 minutes. Turn OFF the engine. Rotate the cooling fan 2 revolutions. Does the cooling fan rotate freely? | Go to Step 7 | Go to Step 13 |
| 7 | Disconnect 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 clutch and ground. Does the test lamp illuminate? | Go to Step 8 | Go to Step 11 |
| 8 | Disconnect the cooling fan relay. Does the test lamp remain illuminated? | Go to Step 9 | Go to Step 10 |
| 9 | Repair the cooling fan clutch supply voltage circuit of the cooling fan clutch for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | |
| 10 | Inspect for poor connections at the cooling fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
| 11 | Inspect for poor connections at the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 12 | Replace the cooling fan relay. Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 14 | |
| 14 | Use 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 2 | System OK |
| IMPORTANT |
|---|
| DTC P1482, for 4.2L (LL8), and P0480, for 5.3L (LM4), will set when the cooling fan relay is disconnected. |
| IMPORTANT |
|---|
| Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan clutch to 100 percent 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. |
DTC P0495
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests that the PCM receives a cooling fan speed signal through the cooling fan speed signal circuit. If answer to question is Yes, refer to all Diagnostic Aids.
- 3: This step tests for the proper operation of the cooling fan clutch hall effect sensor. The voltage should fluctuate between 0-5 volts. If the voltage stays at 0 volts, the signal circuit is shorted to ground.
- 4: This step tests for the proper operation of the 5-volt reference circuit and of the low reference circuit of the cooling fan clutch.
| Step | Action | Values | 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 | Install a scan tool. Start the engine. With the scan tool, observe the Fan Speed parameter in the powertrain control module (PCM) ENG 2 data list. Does the scan tool indicate that the Fan Speed parameter is within the specified range? | Approximately 800 RPM | Go to Diagnostic Aids | Go to Step 3 |
| 3 | Turn 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 Measure the voltage of the cooling fan speed sensor circuit and a good ground. Turn ON the ignition, with the engine OFF. Manually rotate the cooling fan clutch. Does the voltage change from 0 to 5 volts? | 0-5 V | Go to Step 10 | Go to Step 4 |
| 4 | Disconnect the jumper wires. Measure the voltage between the 5-volt reference circuit and the low reference circuit of the cooling fan clutch. Is the voltage measurement near than the specified value? | 5 V | Go to Step 7 | Go to Step 5 |
| 5 | Turn 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 6 | Go to Step 9 | |
| 6 | Test the 5-volt reference circuit of the cooling fan clutch for a high resistance, or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 7 | |
| 7 | Test 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 to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 8 | |
| 8 | Test the cooling fan speed signal circuit of the cooling fan clutch for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 9 | Test the low reference circuit of the cooling fan clutch for a high resistance or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 10 | Disconnect the jumper wires. Test the cooling fan speed signal circuit of the cooling fan clutch for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 11 | Inspect for a poor connection at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 12 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | ||
| 15 | Use 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 2 | System OK | |
DTC P0526
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests that the PCM receives a cooling fan speed signal through the cooling fan speed signal circuit. If answer to question is Yes, refer to all Diagnostic Aids.
- 3: This step tests for the proper operation of the clutch hall effect sensor.
- 4: This step tests for the proper operation of the 5-volt reference circuit and of the low reference circuit of the cooling fan.
| Step | Action | Values | 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 | Install a scan tool. Start the engine. With the scan tool, observe the Fan Speed parameter in the powertrain control module (PCM) ENG 3 data list. Does the scan tool indicate that the Fan Speed parameter is within the specified range? | 550-800 RPM | Go to Diagnostic Aids | Go to Step 3 |
| 3 | Turn 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 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 V | Go to Step 10 | Go to Step 4 |
| 4 | Disconnect 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 V | Go to Step 5 | Go to Step 7 |
| 5 | Turn 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 6 | Go to Step 9 | |
| 6 | Test the 5-volt reference circuit of the cooling fan clutch for a high resistance, or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 7 | |
| 7 | Test 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 to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 8 | |
| 8 | Test the cooling fan speed signal circuit of the cooling fan clutch for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 9 | Disconnect the PCM. Test the low reference circuit of the cooling fan for a high resistance or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 10 | Disconnect the jumper wires. Test the cooling fan speed signal circuit of the cooling fan clutch for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 11 | Inspect for a poor connection at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 12 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | ||
| 15 | Use 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 2 | System OK | |
DTC P1481
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, the answer is No.
- 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, answer Yes.
- 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.
- 5: Tests for the ability of the PCM to control cooling fan clutch speed. If answer to question is Yes, refer to all Diagnostic Aids.
- 6: Verifies the ignition 1 voltage circuit of the cooling fan relay.
| Step | Action | Values | 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 | With 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 5 | Go to Step 3 | |
| 3 | IMPORTANT: 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 2,000 RPM for 2 minutes. Does the cooling fan engage? | Go to Step 4 | Go to Step 5 | |
| 4 | IMPORTANT: Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan to 100 percent 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 2,000 RPM for 2 minutes. Does the cooling fan clutch disengage? | Go to Step 5 | Go to Step 17 | |
| 5 | Install a scan tool. Start the engine. Observe the Fan Speed parameter in the powertrain control module (PCM) Output Controls. With a scan tool, command the fan speed to increase. Does the Fan Speed increase? | Go to Diagnostic Aids | Go to Step 6 | |
| 6 | Turn 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 7 | Go to Step 11 | |
| 7 | Test 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 19 | Go to Step 8 | |
| 8 | Test 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 19 | Go to Step 9 | |
| 9 | Connect a test lamp to the cooling fan clutch control circuit of the cooling fan relay and ground. Connect a 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 percent. Is the frequency less than the specified value? | OL | Go to Step 14 | Go to Step 10 |
| 10 | Command the Fan Control to 100 percent. Does the frequency fluctuate? | Go to Step 13 | Go to Step 14 | |
| 11 | Inspect the Eng Fan fuse. Is the fuse open? | Go to Step 12 | Go to Step 15 | |
| 12 | Test 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 19 | Go to Step 15 | |
| 13 | Inspect 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 19 | Go to Step 16 | |
| 14 | Inspect 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 19 | Go to Step 18 | |
| 15 | Repair 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 | ||
| 16 | Replace the cooling fan relay. Did you complete the replacement? | Go to Step 19 | ||
| 17 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement Did you complete the replacement? | Go to Step 19 | ||
| 18 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 19 | ||
| 19 | Use 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 2 | System 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 powertrain control module (PCM) commanding the cooling fan to 100 percent 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 P1482
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, the answer is No.
- 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, answer Yes.
- 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.
- 5: This step tests the PCM's ability to control the cooling fan. If answer to question is Yes, refer to all Diagnostic Aids.
- 6: This step inspects for a mechanical condition which causes the DTC to set.
- 7: This step 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.
- 8: This step tests the cooling fan relay for a PWM signal on the cooling fan clutch supply voltage circuit of the cooling fan clutch.
| Step | Action | Values | 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 | With 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 5 | Go to Step 3 | |
| 3 | IMPORTANT: 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 2,000 RPM for 2 minutes. Does the cooling fan engage? | Go to Step 4 | Go to Step 5 | |
| 4 | IMPORTANT: Continuously excessive fan noise is due to the powertrain control module (PCM) commanding the cooling fan to 100 percent 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 2,000 RPM for 2 minutes. Does the cooling fan clutch disengage? | Go to Step 5 | Go to Step 18 | |
| 5 | Install 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 percent. Operate the engine at 2,000 RPM for 2 minutes. Is the Desired Fan Speed within the specified speed of the Fan Speed? | 1,000 RPM | Go to Diagnostic Aids | Go to Step 6 |
| 6 | Turn 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 20 | Go to Step 7 | |
| 7 | Disconnect the cooling fan clutch connector at the fan shroud. Connect a jumper wire between each of the cooling fan clutch circuits. Connect a DMM between the clutch supply voltage circuit of the cooling fan clutch and ground. Start the engine. Command the Fan Control to 0 percent. Does the voltage measure greater than the specified value? | 0.16 V | Go to Step 10 | Go to Step 8 |
| 8 | Command the fan control to 100 percent. Does the voltage fluctuate? | Go to Step 11 | Go to Step 9 | |
| 9 | Turn 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 12 | Go to Step 17 | |
| 10 | Disconnect the cooling fan relay. Does the voltage measure greater than the specified value? | 0.16 V | Go to Step 14 | Go to Step 11 |
| 11 | Test the cooling fan clutch ground for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 16 | |
| 12 | Test the ground circuit of the cooling fan relay for an open or a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 13 | |
| 13 | Test the clutch supply voltage circuit of the cooling fan clutch for an open or a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 15 | |
| 14 | Test the clutch supply voltage circuit of the cooling fan clutch for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | ||
| 15 | Inspect for poor connections at the cooling fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 16 | Inspect for poor connections at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 18 | |
| 17 | Repair 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 | ||
| 18 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 20 | ||
| 19 | Replace the cooling fan relay. Did you complete the replacement? | Go to Step 20 | ||
| 20 | IMPORTANT: 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 2 | System 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 powertrain control module (PCM) commanding the cooling fan to 100 percent 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
| IMPORTANT | Review 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 on the diagnostic table.
- 2: There should be no binding or increased resistance as the cooling fan clutch is rotated.
- 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.
- 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.
- 6: This step clears DTCs that were set during previous steps. Test driving the vehicle will attempt to set DTCs not previous found in the Engine Cooling Diagnostic Check. If no DTC is set, the condition is a normal operation of the cooling fan.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views DEFINITION: The cooling fan clutch has excessive fan noise. | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Rotate the cooling fan 3 complete revolutions? Is the resistance of the cooling fan clutch even throughout each rotation? | Go to Step 4 | Go to Step 3 |
| 3 | Inspect the cooling fan clutch for proper installation. Refer to Fan Clutch Replacement . Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
| 4 | IMPORTANT: 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 5 | Go to Step 7 |
| 5 | 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. Turn OFF the ignition. Remove the 10-amp fused jumper wire. Install the cooling fan relay. Disconnect the cooling fan clutch connector. Start the engine. Raise the engine speed to 2,000 RPM for 2 minutes. Does the cooling fan disengage? | System OK | Go to Step 6 |
| 6 | Turn OFF the ignition. Connect the cooling fan clutch connector. Turn ON the ignition, with the engine OFF. With a scan tool, clear all DTCs. Start the engine. Test drive the vehicle. With a scan tool, observe the DTC list. Does the scan tool display any cooling system DTCs? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| 7 | Inspect 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 9 | Go to Step 8 |
| 8 | Replace the cooling fan clutch. Refer to Fan Clutch Replacement . Did you complete the replacement? | Go to Step 9 | |
| 9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go 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