I have a 94 Ford Explorer and I get a error code 341 ( octane adjust service pin in use ). I can't find anything that tells me how to correct this. Any help is appreciated

 

according to [link:www.dalidesign.com/hbook/3digit.html/|http://www.dalidesign.com/hbook/3digit.html] that code is informational only. I don't know for sure myself, but it may not indicate any kind of fault.

 

My Haynes manual describes the code as "Octane adjust service pin OPEN". The code is only detected during a Key on, engine off test.

I think I have seen this on the wiring harness in the general area of the self test connector leads. On my 91, it is a grey plug, plugged into a wiring harness connector. The wiring diagram shows a shorting bar on a lead from the ECM to the EDIS module (lead color PINK?). I think it is used to slightly advance the timing a few degrees when removed, when higher octane gasolines are used. Do you notice any pinging or do you use higher octane than regular unleaded in the vehicle?
I you really want to clear it, look for a wire plug with 2 leads inside that is missing a shorting plug, then go to the junk yard and get one to fill the hole.

Dialtone

 

I do get some pinging at times. Mild though. I use 87 octane. I don't seem to get the same gas mileage as I use to. On the open road 19-20 miles to the gallon was normal now it's 17-18.

 

The "octane reduction plug" if removed, retards the timing 2-3 degrees, and allows the use of lower octane fuel. At least that's the way it works on my 92 Mustang. I pulled the plug out, and stopped the pinging on mine. There was no change in mpg that I could tell.