P0493
DTC P0483 or P0493 (LGH/LML)
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
Circuit/System Description
The cooling fan relay sends a pulse width modulated (PWM) signal of 12-14 volts to the cooling fan clutch through the cooling fan clutch solenoid voltage control circuit. The cooling fan relay varies the voltage drop across the cooling fan clutch solenoid in relation to a pulse width modulated signal from the ECM in order to control the speed of the cooling fan. The signal controls the position of the oil control valve inside the cooling fan clutch housing.
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 1,200-3,780 RPM.
* The BARO is greater than 75 kPa.
* The engine coolant temperature is warmer than 70°C (158°F).
* The charge air cooler (CAC) down stream temperature is warmer than -7°C (19°F).
* The ECM commanded fan 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 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.
Reference Information
Schematic Reference
Engine Cooling Schematics (Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Cooling Fan Description and Operation (Gas) (Description and Operation)Cooling Fan Description and Operation (Diesel) ()
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 (Control Module References) 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 either 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 cooling fan clutch relay.
2. Test for less than 5 ohm between the fan relay ground circuit terminal 6 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Disconnect the fan clutch harness connector X142.
4. Test for less than 5 ohm between the fan clutch solenoid valve ground circuit terminal A and ground.
• If greater than the specified value, test the ground circuit for an open/high resistance.
5. Install the fan clutch relay.
6. Connect a test lamp between the cooling fan clutch solenoid voltage control circuit terminal B and ground.
Note: Ensure that the test lamp and harness connector are positioned away from the cooling fan, drive belt, and pulleys.
7. Engine operating, command the fan clutch relay to 50 % with a scan tool. The test lamp should illuminate and flash ON and OFF.
• If the test lamp does not illuminate, test the solenoid voltage control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fan clutch relay.
• If the test lamp illuminates without flashing, test the solenoid voltage control circuit for a short to voltage. If the circuit tests normal, replace the fan clutch relay.
8. If all the circuit/connections test normal, test or replace the cooling fan clutch assembly.
Component Testing
Relay Test
1. Remove the cooling fan clutch relay.
2. Connect a 10 A fused jumper wire between relay terminal 2 and B+. Connect a jumper wire between relay terminal 6 and ground.
3. Test for less than 1 V between terminal 4 and ground.
• If greater than the specified value, replace the fan relay.
4. Connect a jumper wire between terminal 5 and ground.
5. Test for B+ between terminal 4 and ground.
• If less than the specified value, replace the fan relay.
EV Fan Clutch Solenoid Valve Test-Static
1. Disconnect the fan clutch jumper harness connector X142.
2. Test for 7-17 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 jumper wire between terminal A of the jumper harness connector and ground.
3. Connect a 10 A fused jumper wire to terminal B 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 fan clutch to fully engage with the engine at idle.
4. Connect the 10 A fused jumper wire to B+. 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 10 A fused jumper wire from B+. 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 (Diesel) ()
* Control Module References (Control Module References) for replacement, setup, and programming