This video explains How to Retrieve Ford OBD I codes on vehicles built between the years of 1985 to 1995 equipped with Ford EEC-IV System.
The process is super simple, and you can do it with an analog voltmeter and a jumper wire. Plus you have the benefit of having a cute Instructor guiding you step by step during the video.
Ford Vehicles built up to 1991 will display 2 digit codes; vehicles built from 1992 to 1995 will display 3 digit codes. The codes will display in sequence, there will be a separator code which is either 11 for 2 digit codes or 111 for 3 digit codes.
After the separator code has been displayed the continuous memory codes will be displayed. Take note that on vehicles built after 1992 the check engine light will also flash the codes once the self test terminals are bridge with the jumper wire and it won’t be necessary to connect the analog voltmeter to read the codes.
Once you have gathered all the codes, proceed to search their meaning and start the troubleshooting process.
Once you have repaired the problem, you can clear the codes by starting the KOEO self test and when the codes start to display either on the voltmeter or the check engine light in the instrument panel remove the jumper wire from the Diagnostic Test Connector.