The computer in modern Ford vehicles is called a "power train control module." Part of its job is to monitor the drive-train management systems, emissions systems and other related components. Diagnostic trouble codes are generated in the power train control module in the 1995 Ford F-150 when the module detects an error in any of the monitored systems. This in turn illuminates the Check Engine light on 1995 F-150's instrument panel to alert you there’s a malfunction that needs to be repaired. The diagnostic trouble codes correspond to pinpoint troubleshooting tests, which allow repair technicians to properly diagnose and repair the issue.
Plug a scan tool’s data-link cable into the 1995 Ford F-150's diagnostic port. The port is located underneath the driver’s side of the dashboard; it has a small, black cover over it to protect it from contamination. You will need to remove the cover by hand to expose the connector’s pins, which mate to the data-link cable.
Turn the ignition key to the run position and turn on the scan tool if it does not come on automatically after you turn the ignition key.
Follow the scan tool’s specific operating instructions for running a self test on the F-150’s power train control module. This will reveal the trouble codes that have been stored.
Write the codes on a piece of paper for reference during the diagnosis and repair stages.
Clear the codes when prompted to do so by the scan tool if the malfunction has been corrected. Do not clear the codes until you have repaired the malfunction. Doing so will simply give the power train control module a rudimentary form of amnesia and make diagnosing the issue more difficult. If you need to disconnect the scan tool and diagnose the issue later, simply decline to erase them when prompted to do so, and finish out the self test.
Disconnect the scan tool when the test is complete. Don’t forget reinstall the diagnostic port cover when you are done.
