P0480
DTC P0480 or P0481 (2.4)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0480
- Low Speed Cooling Fan Relay Control Circuit
DTC P0481
- High Speed Cooling Fan Relay Control Circuit
Diagnostic Fault Information
P Codes:
Circuit/System Description
The engine control module (ECM) grounds the low speed relay, which is relay 1, and the high speed relay, which is relay 2, control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.
Conditions for Running the DTC
* The ignition is ON.
* The system voltage is between 9-18 volts.
Conditions for Setting the DTC
* An improper voltage level has been detected on the cooling fan relay control circuit.
* The condition must be present for a minimum of 30 seconds.
Action Taken When the DTC Sets
* DTC P0480 is a Type B DTC.
* DTC P0481 is a Type B DTC.
Conditions for Clearing the DTC
* DTC P0480 is a Type B DTC.
* DTC P0481 is a Type B DTC.
Reference Information
Schematic Reference
Engine Cooling Schematics (LE5) (Electrical Diagrams)Engine Cooling Schematics (LNF) (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Cooling Fan Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Electrical Center Identification Views (Application and ID)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, command each relay ON and OFF with a scan tool. Feel or listen to verify that each relay turns ON and OFF with each command.
Circuit/System Testing
1. Ignition OFF, disconnect the affected relay.
2. Ignition ON, connect a test lamp between the positive terminal at the battery and the relay control circuit terminal.
* Cooling Fan Relay 1 = Terminal 86
* Cooling Fan Relay 2 = Terminal 85
3. Command the relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If the test lamp is always OFF, test the relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
4. Connect a 30A fused jumper between the positive voltage terminal at the battery and the fan voltage supply circuit terminal and verify fan activation.
* Cooling Fan Relay 1 = Terminal 87
* Cooling Fan Relay 2 = Terminal 30
• If the fan does not activate, test the fan voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fan.
5. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal and verify fan activation.
For the Relay Switch Voltage Supply Circuit
* Cooling Fan Relay 1 = Terminal 30
* Cooling Fan Relay 2 = Terminal 87
For the Fan Voltage Supply Circuit
* Cooling Fan Relay 1 = Terminal 87
* Cooling Fan Relay 2 = Terminal 30
• If the fan does not activate, test the relay switch voltage supply circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the relay.
6. Ignition ON, verify that a test lamp illuminates between the relay coil voltage supply circuit terminal and ground.
* Cooling Fan Relay 1 = Terminal 85
* Cooling Fan Relay 2 = Terminal 86
• If the test lamp does not illuminate, test the relay coil voltage supply circuit for a short to ground or an open/high resistance.
• If the circuit tests normal and its fuse is open, replace the relay.
7. If all circuits and the ECM test normal, replace the affected relay.
Repair Instructions
Cooling Fan and Shroud Replacement (Service and Repair)
Repair Verification
Ignition ON, command the relay ON and OFF with a scan tool. Feel or listen to verify that the relay turns ON and OFF with each command.