I decided to run a KOEO code test on my truck. Well after having to repeat the test three times due to not catching the pause time between flashes, I have a mess of numbers to unscramble. I may go out with a camcorder tomarrow and record the series so I can follow it more closely.

There were acouple numbers that match with each try but the rest of the numbers arent on the codes chart.

Where am I going wrong with this. Is there a different chart than the one in my Haynes repair book. The book says that it covers 1980-96 f100 thru f350 models. Is there a certain code chart for each year series?

I have a 91- 4.9. I6.

 

Sometimes the books are wrong. But yo have a 2 digit computer. not the three digit computer of later years. Sometimes it can be hard to time the flashes of the check engine light. Just start over. I have a not pad, and use stick figures for each flash. space when it pauses. then add up the sticks. that way I neve take my eye off the check engine light during the test.

 

'91 is near the changeover for 2 or 3 digit codes, and some will flash both 2 and 3 digit codes. Usually the first KOEO codes will be 2 digit and the continuous will be 3 digit. That in itself makes it that much more confusing.