P0481
DTC P0480 or P0481 (2.2L & 2.4L)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure Initial Inspection and Diagnostic Overview.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach Initial Inspection and Diagnostic Overview.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category Initial Inspection and Diagnostic Overview.
DTC Descriptors
DTC P0480: Cooling Fan Relay 1 Control Circuit
DTC P0481: Cooling Fan Relay 2 Control Circuit
Diagnostic Fault Information
Circuit/System Description
2.2L-L61
The engine cooling fan system is composed of one cooling fan, two relays, the engine control module (ECM), and the associated wiring. The cooling fan has two windings in the motor, one winding is for low speed and the other winding is for high speed. Voltage is supplied to each relay through two individual 30 amp fuses. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.
2.4L-LE5
The engine cooling fan system is composed of one cooling fan, two relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes a single 0.3 ohm resistor mounted in the cooling fan shroud. Voltage is supplied to each relay through two individual 30 amp fuses. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.
Conditions for Running the DTC
- The system voltage is between 11-18 volts.
- The engine speed is greater than 400 RPM.
- The ECM driver transitions from ON to OFF or from OFF to ON.
- The DTCs run continuously once the conditions above have been met.
Conditions for Setting the DTC
- The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match.
- The condition exists for greater than 30 seconds.
Action Taken When the DTC Sets
DTCs P0480 and P0481 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0480 and P0481 are Type B DTCs.
Reference Information
Schematic Reference
Engine Cooling Schematics Electrical Diagrams
Connector End View Reference
- Master Electrical Component List Diagrams
- 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
- Testing for Intermittent Conditions and Poor Connections Component Tests and General Diagnostics
- Wiring Repairs Component Tests and General Diagnostics
- Electrical Center Identification Views Locations
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Diagnostic Trouble Code Descriptions
Scan Tool Reference
Control Module References for scan tool information Control Module References
Circuit/System Verification
1. Ignition ON, command each KR20 cooling fan relay ON and OFF with a scan tool. Listen or feel the relay click.
2. Engine operating, observe the DTC information with a scan tool. DTC P0480 or P0481 should not set.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect both KR20 Cooling Fan Relays.
Note: The following tests must be performed on each fan relay control circuit.
2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil B+ circuit terminal listed below:
- KR20C low speed COOL FAN 1 relay terminal 85
- KR20D high speed COOL FAN 2 relay terminal 85
-> If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the output control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the G10 engine cooling fan.
Note: The following tests must be performed on each fan relay control circuit.
3. Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode setting. The DMM should display OL:
- KR20C low speed COOL FAN 1 relay terminal 86
- KR20D high speed COOL FAN 2 relay terminal 86
-> If less than the specified range, test the appropriate relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
Note: The following tests must be performed on each fan relay.
4. Command the KR20 cooling fan relay ON and OFF with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON.
-> If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the appropriate KR20 cooling fan relay.
Component Testing
1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 70-110 ohms between terminals 85 and 86.
3. Measure the resistance between the terminals listed below. The DMM should display OL:
- 30 and 86
- 30 and 87
- 30 and 85
- 85 and 87
-> If less than the specified range, replace the KR20 cooling fan relay.
4. Connect a 20 A fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
-> If greater than the specified range, replace the KR20 cooling fan relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Cooling Fan and Shroud Replacement Service and Repair
- Control Module References Control Module References