Greetings all. Trying to figure out an issue with my 1993 Ford F250 460 Automatic 4WD. Took my son's and my dual sports with us on a trip out to Colorado. Had the bikes loaded in the bed of my truck. Rolling along fine for a couple of hours and then had to slow down with traffic entering a town on the route. Right after this slow down from about 70 to say 40, I got CEL on the dash. CEL stayed on until I pulled off, shut the engine off, and started it again. CEL then stayed off for a while until I did this same slow down again entering another town. It stays on until I shut engine off and start it again. One time it came on, and then went off, but most of the time it comes on and stays on until I shut engine off for gas stops, etc.

Once we got to Colorado, I used the truck to move trash off our property out there. On and off highway speeds, no bikes in the back. Never got a CEL the week we were there. On the way back again with bikes loaded, I started getting this intermittent CEL. Same deal as before. I am totally new to this truck as I have only had it less than a year. I got curious and got an ODB1 code reader (Innova 3145). Pulled codes when I got back to town. I am totally new to ODB1 but this is what I got when I ran the KOEO test:

Sect 1

Code 67

Sect 2

Code 41
Code 62
Code 67
Code 41
Code 62
Code 67

Sorry here, I admittedly need to educate myself on how ODB1 works so sorry if the above does not make sense. When I run the KOEO test, there are two 'sections': One with the tester lit up with an 'o' and then another section lit up with a 'c'.

Best I can tell here, code 62 is a transmission code which I have read may be a torque converter slip detection code. Code 41 is system lean - fuel control code. The 62 code makes sense as it only seems to happen with 600 pounds of dual sport bikes in the bed.

I should mention, I do not detect any real performance change with the CEL comes on. Truck seems to run fine, plenty of power, etc.

While I try and educate myself here on ODB1 systems, these codes and what they mean, was hoping maybe someone could point me in the right direction as to what could be going on here. Thanks in advance for any guidance.

 

You probably need to adjust the MLP lever position on the transmission. There are videos to show you the simple procedure. I just replaced mine since I kept getting the code and trans wasn't acting correctly. All good now.

67 Park/Neutral circuit fault - PNP
Transmission Manual Lever Position (MLP) sensor circuit - Transmissions

Your other codes are in MEMORY which means they did happen for an instant but were not permanent. Therefore they are considered soft codes and not currently active. Best bet is to clear those memory codes. Instructions in book to clear them. Then get the truck to operating temp. and run the codes again and see what you get.

You may have the older style MLP so this thread of my MLP adventures may help you.
https://www.ford-trucks.com/forums/1...mlps-help.html

 

Thanks for the reply here. So I am clear, with ODB1, the 67 code is a current code that's happening now when I run the test. The other code (when the 'c' is lit up) are codes that have happened in the past but are not currently occurring? Sound right? I have no CEL on right now at all. Can I assume it was just a temporary thing then and not worry about it, or should I try and address the soft codes to keep them from happening again? Thanks again for your reply here.

 

Yes the 67 is your current code based on your post. I would clear the memory codes and retest just to make sure they are gone and then next time you drive it run KOEO again and see what is in there. If they keep coming back in memory some test may be in order. Your codes repeat on the Memory section and is normal.

 

So with ODB1, when the CEL comes on, that means a DTC has been set correct? Its then stored in memory for later retrieval. With my CEL, it comes on and stays on until I shut the engine off and start it again. My CEL is off right now without doing anything other than shutting off the motor and starting it again. This is counter to my experience with ODBII cars. You can clear the codes and have the light go out or don't clear them and the light stays on. Is this just a difference between how ODBI and ODBII store codes or does the fact that my CEL goes out after restarting the engine mean something else in my case. As I mention, I actually had the CEL come on and stay on for like 30 minutes and then go out all by itself while driving along. Not sure I understand why that would be. Asking for a friend

 

Also on the 62 code, I am reading that it usually points to a worn torque converter. Might explain why I got this only with the bikes in the bed. Extra weight caused it to slip. I would like to keep this truck so not opposed to getting that replaced. I don't feel it slip myself and cannot see significant changes in the tach RPM while driving that might illustrate a slip situation. Maybe just ignore it until it's an actual issue for me?

 

I'm not sure about the CEL going out on 62 but I assume when it did it went to Memory. It set the hard code for the TC then it cleared and went from hard code to soft. ???? Also FYI you do not have to have a CEL to have a hard code. It happens often on the forum. I run my reader about once a month just to be cautious and to see what is in Memory.

 

I would not do anything now except be aware and check my codes frequently. If the 62 appears with a CEL or hard code you can decide what action to take. Folks replace the TC on the forum without a lot of experience and the forum can help you do it properly. You should start having some slipping shifts it the TC is going out and you will know what it is. Hopefully the TC code was from the weight and conditions.

 

So on the code 41 (Oxygen sensor circuit indicates system always lean), would that indicate a possible issue with the o2 sensor? I see only one on this 460 truck, right at the Y-pipe. I couldn't see any o2 sensors further up on the manifolds so guessing that's the only place on this '93 460 where the o2 sensor is. Truck runs pretty good for the most part, but sometimes the idle seems a bit rough and sometimes when it's hot and I stop it and let it sit for about 30 minutes, when I start it again it seems to want to die. Giving it some gas gets it back to normal idle RPM. Not trying to figure that out with this thread, but just adding it here in the event it helps some with context and the 41 code. Thanks again for all the input.

 

Code 41 could also be caused by low fuel pressure, a leaking exhaust manifold, or leaking AIR injector system.

 

OK thankyou here. Gives me a place to start. Thanks again.

Is there a good source for 460 o2 sensors that anyone would recommend?

 

The 41 code can be tricky. Rather than just replace the sensor, (my 91 has only one also) you should test it first.
https://easyautodiagnostics.com/ford...e-o2-sensor-do

 

41 Heated oxygen sensor (H02S), bank 1 mixture leanlnot switching Intake leak, fuel pressure low, fuel filterl pump, injectors, H02S, AIR system, MAF/MAP sensor, ECM

41 code can also be caused by the engine not being at operating temp when test was run.. Your 41 was in memory so it is not active.

 

I had a '92 Aerostar that would do the same thing every time it was driven over two hours straight. Did it for a few years. I changed the o2 sensor, and that fixed it.

 

So I was able to book time to clear the codes (ie disconnect negative battery cable). Ran and check and memory codes are cleared now. Still get a 67 for KOEO test, but I think I had the A/C on when I ran it which I think will show code 67 (67 Park/Neutral Position (PNP) switch circuit open - A/C on during Self-Test.). So I'll rerun without AC and see what that's about.

Will keep checking on this periodically. No CEL around home for almost a year and then long trip and it comes up. Thanks for all the replies here.

Edit: Sure enough I re-ran the test with the A/C off and now no codes. Clean as a whistle. Will keep checking with reader periodically. Thanks again for the replies.