P0483
DTC P0483 or P0493
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
DTC Descriptor
DTC P0483
- Cooling Fan System Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The electro-viscous (EV) cooling fan clutch system enables the engine control module (ECM) to change the speed of the pulley driven cooling fan in relation to the engine speed. Ignition voltage is supplied directly to the fan clutch solenoid valve. The ECM uses two output drivers and a parallel circuit to directly control the EV fan clutch solenoid valve. The ECM controls the solenoid valve by pulse width modulating (PWM) the parallel control circuits to ground, with a solid state device called a driver. The ECM changes the cooling fan speed by increasing or decreasing the solenoid valve ON time, known as duty cycle.
Conditions for Running the DTC
* DTC P0016, P007C, P007D, P0112, P0113, P0117, P0118, P0335, P0336, P0340, P0341, P0480, P0495, or P0526 is not set.
* The engine is operating for greater than 10 seconds.
* The engine speed is between 1,200-3,429 RPM.
* The BARO is greater than 75 kPa.
* The engine coolant temperature is warmer than 70°C (158°F).
* The ECM commanded fan clutch solenoid duty cycle is greater than 36 percent.
* The cooling fan input shaft speed is steady.
* DTC P0483 runs continuously every 100 mS when the conditions above exist.
Conditions for Setting the DTC
* The difference between the desired and the actual cooling fan speeds is 500 RPM or greater.
* The condition exists for greater than 2 minutes.
Action Taken When the DTC Sets
DTC P0483 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0483 is a Type B DTC.
Diagnostic Aids
The scan tool FC Ckt 2 Test Status parameters can be used in conjunction with the FC Ckt Test Status parameters to verify the integrity of the individual control circuits. If both the scan tool FC Ckt and FC Ckt 2 parameters indicate Fault in the respective Open Test Status then the condition is isolated to the portion of relay control circuit that is after the splice and common to both drivers. If Fault is indicated in only FC Ckt or FC Ckt 2, then the condition is isolated to the respective output driver and the portion of the circuit before the splice.
Reference Information
Schematic Reference
Engine Cooling Schematics ([1][2]Cooling System)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Cooling Fan Description and Operation (Cooling Fan)
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 (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Ignition OFF, inspect the cooling fan and the drive belt for the following conditions:
* A loose, worn, or mis-routed drive belt
* Oil leaks at the cooling fan clutch
* A free-spinning cooling fan
* A seized cooling fan clutch
* A broken cooling fan
2. Ignition ON, observe the DTC information with a scan tool. Verify DTC P0480 or P0526 is not set.
• if a DTC is set diagnose that DTC first.
3. Operate the engine at 1,500 RPM while slowly commanding the cooling fan clutch from 10 % to 80 %, then return to 10 %. Observe the difference between the scan tool Fan Speed and Desired Fan Speed parameters throughout the test. The difference between the parameters should be less than 500 RPM throughout the speed transition.
4. Observe the DTC information with a scan tool. Verify DTC P0483 is not set.
5. 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 the fan clutch solenoid valve jumper harness connector X142.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal B and ground.
• If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test the fan clutch solenoid and jumper harness for a short to ground.
3. Test for 3-4 V between the solenoid control circuit terminal A and ground.
• If less than the specified range, test the control circuit for an open/high resistance or for a short to ground. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the relay control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Connect a 3 A fused jumper wire between the solenoid control circuit terminal A and ground. Observe the scan tool Test Status parameters listed below:
* FC Ckt Short Gnd Test Status
* FC Ckt 2 Short Gnd Test Status
Both parameters should transition from OK to Fault when the control circuit is connected to ground.
• If both parameters do not respond as specified, test the solenoid control circuit for a high resistance.
• If only one of the parameters responds as specified, test the appropriate solenoid control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the cooling fan clutch assembly.
Component Testing
EV Fan Clutch Solenoid Valve Test-Static
1. Disconnect the fan clutch jumper harness connector X142.
2. Test for 5-12 ohm between terminal B and terminal A of the jumper harness connector.
• If not within the specified range, replace the fan clutch assembly.
3. Measure the resistance between the terminals listed below. The DMM should display OL.
* B and C
* B and D
* B and E
* B and the fan clutch housing
• If less than the specified range, test the circuits of the jumper harness for an open/shorted condition. If the jumper harness tests normal, replace the cooling fan clutch assembly.
EV Fan Clutch Solenoid Valve Test-Dynamic
1. Ignition OFF, disconnect the fan clutch jumper harness connector X142.
2. Connect a 10 A fused jumper wire between terminal B of jumper harness connector and B+.
3. Connect a jumper wire to terminal A of the jumper harness connector.
Note:
* Ensure that the jumper wires and harness connector are positioned away from the cooling fan, drive belt, and pulleys.
* It may take several minutes for the clutch to fully engage with the engine at idle.
4. Engine operating, connect the jumper wire from terminal A to ground. The fan should get much louder to indicate the clutch is engaged.
Note: It may take anywhere from 10-52 minutes for the fan clutch to disengage depending on the factors below:
* Engine speed
* Coupler fluid temperature
* Elevation above sea level
5. Disconnect the ground from the jumper wire connected to terminal A. The fan should become quiet to indicate the clutch is disengaged.
• If the fan clutch doesn't engage or disengage according to the test, replace the cooling fan clutch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Fan Clutch Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for replacement, setup, and programming