P0481
P0481 - Cooling Fan 2 Control Circuit
For wiring diagrams, refer to.
• When Monitored: With the engine running, battery voltage greater than 10.4 volts, and the cooling fan 2 control active.
• Set Condition: The PCM detects an open or shorted condition in the cooling fan 2 control circuit.
• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - DTC is Active
• Turn the ignition ON.
• With the scan tool, actuate the cooling fan 2 control.
• With the scan tool, select view DTCs.
Is the status active for this DTC?
Yes
• Go to Test Step 2 => [ Test
Step 2 - Radiator Fan High Speed Control Circuit Shorted to Voltage ]
No
• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC
Test Step 2 - Radiator Fan High Speed Control Circuit Shorted to Voltage
• Turn the ignition OFF.
• Disconnect the radiator fan high relay connector.
• Disconnect the C3 totally integrated power module harness connector.
• Turn the ignition ON.
• Measure the voltage of the radiator fan high speed control circuit in the radiator fan high relay harness connector.
Is there any voltage present?
Yes
• Repair the radiator fan high speed control circuit for a short to voltage.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 3 => [ Test
Step 3 - Radiator Fan High Speed Control Circuit Shorted to Ground ]
Test Step 3 - Radiator Fan High Speed Control Circuit Shorted to Ground
• Turn the ignition OFF.
• Measure the resistance between ground and the radiator fan high speed control circuit in the radiator fan high relay harness connector.
Is the resistance less than 100 ohms?
Yes
• Repair the short to ground in the radiator fan high speed control circuit.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 4 => [ Test
Step 4 - Radiator Fan High Speed Control Circuit Open or High Resistance ]
Test Step 4 - Radiator Fan High Speed Control Circuit Open or High Resistance
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
• Measure the resistance of the radiator fan high speed control circuit between the radiator fan high relay harness connector and the appropriate terminal of special tool #8815.
Is the resistance less than 5.0 ohms?
Yes
• Go to Test Step 5 => [ Test
Step 5 - Radiator Fan High Relay Control Actuation ]
No
• Repair the radiator fan high speed control circuit for an open or high resistance.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 5 - Radiator Fan High Relay Control Actuation
• Connect the totally integrated power module connector.
• Turn the ignition ON.
• With the scan tool, actuate the cooling fan 2 control to ON.
• Using a test lamp connected to ground, check the radiator fan high speed control circuit in the radiator fan high relay harness connector.
• The test lamp should be illuminated and bright proportional to the maximum duty cycle allowed by the scan tool. For example, if the scan tool allows 100% actuation, the brightness should be as bright as a direct connection to the battery. If the scan tool allows a maximum 25% actuation, the brightness should be 25% as bright as a direct connection to the battery.
• With the scan tool, actuate the radiator fan high relay control to OFF.
• Using a test lamp connected to ground, check the radiator fan high speed control circuit in the radiator fan high relay harness connector.
• The test lamp should not be illuminated with the control actuated OFF (0%).
Is the test lamp illuminated when actuated ON and not illuminated when actuated OFF as described?
Yes
• Go to Test Step 6 => [ Test
Step 6 - Radiator Fan High Relay ]
No
• Go to Test Step 7 => [ Test
Step 7 - Totally Integrated Power Module ]
Test Step 6 - Radiator Fan High Relay
• Turn the ignition OFF.
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the radiator fan high relay and the totally integrated power module.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace the radiator fan high relay.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 7 - Totally Integrated Power Module
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the radiator fan high relay and the totally integrated power module.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
• Refer to any technical service bulletins that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace and program the totally integrated power module.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test