By October 23, 2012 0 Comments Read More →

How To Read Check Engine Codes

Hey Austin,

I rented that EEC-4 from the local parts store, and I am even more so worried now… I got 6 different codes, and some of them were repeats. I did 2 scans, one with the key in the “ready to start” possition and another scan while i was rev-ing the engine to keep it running. As for codes I got:

KOEO: 23, 31, (41 in KOEO only when i constantly reved the car to keep it on)

MEMORY: 31, 18, 41

KOER:41, 22, 21

I dunno if you know the defitinitions by heart, or if its on a paper near by, but the EEC i used had built in definition summerys so i’ll include that too, (skip it if ya dont need it!!)

23: Throttle position sensor out of range

31: EGR valve position or exaust pressure transducer sensor voltage low

18: Loss of ignition diagonostic monitor signal to controll module / Spark output grounded

41: No exaust gas oxygen switching dected always indicating lean

22: Manifold air pressure or BARO pressure sensor is out of range

21: Coolant temp out of range

Oh and yeah the car is fuel injected, no carburator. Other than that, i dunno what else to tell you that may help. I already mentioned the V8 – 5.0L and its a 85 Mercury Cougar… Anything else that would be relevent let me know. I am going to check the EGR valve, and the pump pressure. I am pretty sure my exhaust isnt cloged, it has some pressure behind it, and there is a crack in the exaust pipe about half way down it, about the same place as a trucks ext-exaust caps would be. I dont really know how to check the ignition timing, or a timing chains slack.

But thanks agin for your time, maby you can help me before i have to pay the unhonnest mechanic…ha ha. I do look foward to hearing from ya


Hey Jonathan

Have you tried Alldata? I REALLY like it, and its cheap and easy to use.

Check it out here Auto Repair Manuals

I am not really going to be able to help you much with those codes .it will get technical and I would probably need to be there to show you how to test those sensors to see if there really is a problem or not. I AM still suspect of the EGR valve.

If you don t want to replace it. Make a gasket that will block off the valve entirely. Go to the part store and tell them you want a piece of gasket material so you can cut it to fit the egr valve.

The theory is to block off the egr gases. So just a piece of flat gasket material will do, remove the valve and put the material down over the hole and remount the valve to no air leaks back into the manifold. That is my best guess, if that does not do it I would recommend Alldata ..and with the codes you have and some time, you should be able to do some tests and figure it out.

Keep me posted


Austin Davis

Posted in: Check Engine Lights

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."