P0495

DTC P0495
Circuit Description
The cooling fan relay sends a pulse width modulation (PWM) signal (12-14 volts) to the cooling fan by the cooling fan clutch supply voltage circuit. The powertrain control module (PCM) uses the PWM signal, which controls the speed of the cooling fan clutch by controlling the position of the oil control valve inside the clutch. If the cooling fan clutch RPM is to high when the PCM is commanding 0 percent, DTC P0495 will set.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0495 Cooling Fan Speed High

Conditions for Running the DTC
^ The engine is running.
^ The system voltage is greater than 8.5 volts.
^ The intake air temperature (IAT) is greater than -7°C (19°F).
^ Zero percent duty cycle is commanded, and the engine RPM has been over 1,800 RPM for at least 120 seconds.

Conditions for Setting the DTC
Cooling fan RPM exceeds 1,600 RPM for 81 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store the conditions as Freeze Frame/Failure Records data.
Conditions for Clearing the MIL/DTC
^ The PCM turns the MIL OFF after the third consecutive trip that the diagnostic procedure has run and passed.
^ Clear the DTC using the Clear DTC Information function of the scan tool.

Diagnostic Aids
^ An inline connector could cause an intermittent DTC. Ensure to test for poor connections and pin retention at all inline connectors. Refer to system schematics for connector and locations.
^ If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections.
^ If DTC's P0495 and P0113 are set and the weather is cold, the cooling fan code may be false. Clear DTC P0495, and after an IAT repair, check if the DTC will reset.

Test Description

Steps 1-7:

Steps 8-14:

The numbers below refer to the step numbers on the diagnostic table.
2. This step ensures that the DTC has failed this ignition cycle. If the scan tool displays Passed, the answer is No.
3. The cooling fan noise should increase as the cooling fan clutch engages. It can take up to 2 minutes for full cooling fan clutch engagement. If cooling fan clutch is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, answer Yes.
4. In the previous step the cooling fan clutch was fully engaged. This step tests to ensure that the cooling fan clutch will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan clutch and a disengaged cooling fan clutch. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
5. Tests the ability of the PCM to control the cooling fan speed. If answer to question is Yes, refer to all Diagnostic Aids.
6. Disconnecting the cooling fan clutch and running the engine ensure that the cooling fan clutch is not engaged. When rotating the cooling fan clutch it should spin freely. If not, the cooling fan clutch will not disengage.