P0480
GENERAL DESCRIPTION
When the ambient air temperature is warm or the airflow across the engine is low, the enginecoolant temperature can become hot. If the coolant temperature becomes too hot, it is possiblethat the engine could be damaged. High coolant temperatures can also cause the A/C system tobe disabled, in order to reduce load on the engine and protect the A/C system components. Thepurpose of activating the engine compartment ventilation fan(s) is to help reduce the enginecoolant temperature to a level that is not threatening to engine performance and maintains the airconditioning system pressure at safe levels.
Electric fan responsible for causing air movement around the engine coolant radiator. The amount of air movement caused by the fan is controlled based on the Vehicle Speed, coolant temperature, A/C pressure status, A/C switch request status, and A/C clutch state. A duty cycle is determined based on these input parameters. This duty cycle corresponds to fan speed which correlates to the amount of air movement caused by the fan. The increased air movement enhances the heat exchanger function of the radiator in the confined space of the enginecompartment, thereby reducing the engine coolant temperature more quickly.
DTC DESCRIPTION
The Delphi EMS system provides for a method of electrically controlling when the fan(s) should beactivated and deactivated based on a variety of engine conditions, including the coolanttemperature, vehicle speed, air conditioning switch status and air conditioning pressurestatus. As the coolant temperature or air conditioning pressure rises, increased airflow is requiredto reduce the engine temperature and A/C system pressure. The engine cooling fan(s) areactivated to increase airflow across the engine components.
Checking power supply to cooling fan relay to cooling fan module and control signals under detecting condition, if the PCM detects short to ground, to battery or open circuit, PCM sets P0480. MIL(Malfunction Indicatin Lamp) turns on when the malfunction lasts till cosecutive 2 driving cycle.
DTC DETECTING CONDITION
SCHEMATIC DIAGRAM
MONITOR DTC STATUS
1. Connect scantool to Data Link Connector(DLC).
2. IG "ON".
3. Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
4. Read "DTC Status" parameter.
5. Is parameter displayed "Present fault"?
YES
> Go to "Inspection & Repair" procedure.
NO
> Fault is intermittent, go to "Verification of vehicle Repair" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to " Power Circuit Inspection " procedure
POWER CIRCUIT INSPECTION
1. Key "OFF".
2. Disconnect the Fan Relay(Low).
3. Key "ON".
4. Measure the voltage between terminal 85 of the Fan Relay(Low) harness connector and chassis ground.
Specification : B+
5. Is the measured voltage within specifications?
YES
> Go to "Control circuit inspection" procedure.
NO
> Check whether the cooling fan fuse(PCU 10A) is open or not installed.
> Check whether the power circuit is Open or Short.
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
CONTROL CIRCUIT INSPECTION
1. IG "OFF"
2. Disconnect the Fan Relay(Low).
3. IG "ON" & ENG "OFF"
4. Measure the voltage between terminal 86 of the Fan Relay(Low) harness connector and chassis ground.
Specification : Approx. 2.5 V
5. Is the measured voltage within specifications?
YES
> Substitute with a known - good Radiatior Fan Relay(Low) and check for proper operation.
If the problem is corrected, replace the Fan Relay(Low) and go to "Verification of Vehicle Repair" procedure.
NO
> Repair Open or Short in control circuit, and go to "Verification of vehicle Repair" procedure.
NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all rediness test have been verified as " Complete "
5. Are any DTCs present ?
YES
> Go to the applicable troubleshoooting procedure.
NO
> System is performing to specification at this time.