P0495

DTC P0495





Steps 1 - 8





Steps 9 - 14

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 by controlling the position of the oil control valve inside the clutch. If the cooling fan RPM is to high when the PCM is commanding 0%, DTC P0495 will set.

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 1800 RPM for at least 120 seconds.

Conditions for Setting the DTC
Cooling fan RPM exceeds 1600 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.
^ If the condition is not present, refer to Testing for Intermittent and Poor Connections.
^ If DTCs 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
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, then the answer is No.
3. The cooling fan noise should increase as the cooling fan engages. It can take up to 2 minutes for full cooling fan engagement. If cooling fan 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, then answer Yes.
4. In the previous step the cooling fan was fully engaged. This step tests to ensure that the cooling fan will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan and a disengaged cooling fan. The cooling fan 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, ensure to refer to all Diagnostic Aids.
6. Disconnecting the cooling fan and running the engine ensure that the cooling fan is not engaged. When rotating the cooling fan it should spin freely. If not then the cooling fan will not disengage.