Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for an audible click when the cooling fan relay operates. Command both the ON and OFF states. Repeat the commands as necessary. The appropriate cooling fan relay is the cooling fan relay that set the DTC.
- 3: Listen for an audible click when the cooling fan relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
| 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 | Turn OFF the A/C. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the appropriate fan relay ON and OFF. Does the appropriate cooling fan relay turn ON and OFF with each command? | Go to Diagnostics Aids | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the appropriate cooling fan relay. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the appropriate cooling fan relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 |
| 4 | Connect a test lamp between the appropriate cooling fan relay control circuit and the ignition 1 voltage circuit of the appropriate cooling fan relay. With a scan tool, command the appropriate fan relay ON and OFF. Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 5 |
| 5 | Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 6 |
| 6 | Test the control circuit of the appropriate 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 10 |
| 7 | Test the control circuit of the appropriate 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 10 |
| 8 | Repair the ignition 1 voltage circuit of the appropriate cooling fan relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | |
| 9 | Inspect for poor connections at the appropriate 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 |
| 10 | Inspect for poor connections at the harness connector of the Engine Control Module (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 13 | Go to Step 12 |
| 11 | Replace the appropriate cooling fan relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 13 | |
| 12 | Replace the ECM. 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: Cooling Fan Relay 1 Control Circuit
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for an audible click when the cooling fan relay operates. Command both the ON and OFF states. Repeat the commands as necessary. The appropriate cooling fan relay is the cooling fan relay that set the DTC.
- 3: Listen for an audible click when the cooling fan relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
| 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 | Turn OFF the A/C. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the appropriate fan relay ON and OFF. Does the appropriate cooling fan relay turn ON and OFF with each command? | Go to Diagnostics Aids | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the appropriate cooling fan relay. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the appropriate cooling fan relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 |
| 4 | Connect a test lamp between the appropriate cooling fan relay control circuit and the ignition 1 voltage circuit of the appropriate cooling fan relay. With a scan tool, command the appropriate fan relay ON and OFF. Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 5 |
| 5 | Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 6 |
| 6 | Test the control circuit of the appropriate 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 10 |
| 7 | Test the control circuit of the appropriate 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 10 |
| 8 | Repair the ignition 1 voltage circuit of the appropriate cooling fan relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | |
| 9 | Inspect for poor connections at the appropriate 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 |
| 10 | Inspect for poor connections at the harness connector of the Engine Control Module (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 13 | Go to Step 12 |
| 11 | Replace the appropriate cooling fan relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 13 | |
| 12 | Replace the ECM. 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 P0481: Cooling Fan Relay 2 and 3 Control Circuit
Cooling Fan Operation
The cooling fans operate in two stages; in both stages both fans run. In stage 1 the two fan motors are connected in series so both fans run at low speed. In stage 2 each fan motor is connected to battery voltage so both fans run at high speed. Cooling fan operation is controlled by the engine control module (ECM) based on inputs from the following
- The A/C request signal
- The vehicle speed sensor (VSS)
- The A/C refrigerant pressure sensor
- The engine coolant temperature (ECT) sensor