P0481
DTC P0480, P0481, P0691, P0692, P0693, or P0694 (3.5L)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure Diagnostic System Check - Vehicle.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach Strategy Based Diagnosis.
DTC Descriptors
DTC P0480: Cooling Fan Relay 1 Control Circuit
DTC P0481: Cooling Fan Relay 2 Control Circuit
DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage
DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The Cooling Fan Relay 1 or the Fan Low Relay, and the Cooling Fan 2 or the Fan Hi Relay are controlled by the powertrain control module (PCM). Battery voltage is supplied to the cooling fan relay coil. The PCM monitors the voltage on the control circuit of the relay. When the relay is OFF, the voltage should be near battery voltage on the control circuit of the relay. When the relay is commanded ON, the voltage will be low on the control circuit of the relay. The PCM will provide ground on the control circuit of the relay using a low side driver.
Conditions for Running the DTC
- The ignition is ON or the engine is running.
- The ignition voltage is between 8 and 18 volts.
- The engine speed is more than 40 RPM.
- DTCs P0480, P0481, P0691, P0692, P0693 and P0694 run continuously once the above conditions are met.
Conditions for Setting the DTC
P0480
The PCM detects an open circuit on the cooling fan 1 relay control circuit.
P0481
The PCM detects an open circuit on the cooling fan 2 relay control circuit.
P0691
The PCM detects a short to ground on the cooling fan 1 relay control circuit.
P0692
The PCM detects a short to voltage on the cooling fan 1 relay control circuit.
P0693
The PCM detects a short to ground on the cooling fan 2 relay control circuit.
P0694
The PCM detects a short to voltage on the cooling fan 2 relay control circuit.
The PCM detects a short to voltage, a short to ground, or an open/high resistance on the cooling fan relay control circuits.
Action Taken When the DTC Sets
- DTCs P0480 and P0481 are Type B DTCs.
- DTCs P0691, P0692, P0693 and P0694 are Type C DTCs.
Conditions for Clearing the MIL/DTC
- DTCs P0480 and P0481 are Type B DTCs.
- DTCs P0691, P0692, P0693 and P0694 are Type C DTCs.
Diagnostic Aids
The following two tables illustrate the COOLING FAN 1 relay and the COOLING FAN 2 relay terminal locations in the underhood fuse block. The third table illustrates the COOLING FAN 3 relay terminal locations in the relay electrical connector.
COOL FAN 1 Relay
COOL FAN 2 Relay
COOLING FAN 3 Relay
Reference Information
Schematic Reference
Engine Cooling Schematics Electrical Diagrams
Connector End View Reference
Cooling System Connector End Views Connector Views
Description and Operation
Cooling System Description and Operation Description and Operation
Electrical Information Reference
- Circuit Testing Circuit Testing
- Connector Repairs Connector Repairs
- Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
- Scan Tool Output Controls Scan Tool Testing and Procedures
- Scan Tool Data List Scan Tool Testing and Procedures
- Scan Tool Data Definitions Scan Tool Testing and Procedures
Circuit/System Verification
1. Ignition ON, command the appropriate cooling fan relay ON and OFF with a scan tool. Listen or feel for the relay to click.
2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
1. Ignition OFF, disconnect the appropriate cooling fan relay.
2. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit and ground.
-> If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the relay coil ignition circuit and replace as necessary.
3. Connect a test lamp between the relay coil ignition circuit and the relay coil control circuit.
4. Command the cooling fan 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 coil control circuit for a short to ground. If the circuit tests normal, replace the PCM.
-> If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM.
5. If all circuits test normal, test or replace the appropriate cooling fan relay.
Component Testing
1. Ignition OFF, disconnect the appropriate cooling fan relay.
2. Test for 70-110 ohms of resistance between terminals 85 and 86.
-> If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
- 30 and 86
- 30 and 87
- 30 and 85
- 85 and 87
-> If not the specified value, replace the relay.
-> If greater than the specified range, replace the relay.
4. Install a 20A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms of resistance between terminals 30 and 87.
-> If greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Relay Replacement Service and Repair
- Control Module References for PCM replacement, setup, and programming Control Module References