Hello,

I am having some problems with the codes on my 1989 Ford F350. A little history first I think will help. It is a 89 F350 4x4 7.5l with an E40D. It has been parked since 2009. I started to do some work on it and took the tranny out of a 1997 Ford F250 4x4 with a 7.5l. Swaped the trannys. I also swapped the EEC-IV's as well. I went to run a EEC test tonight and this is what I came up with. KOEO test came up with 126, and 553. KOER came up with 126 and 998. From what I have read the 998 code could have something to do with codes showing up on the KOEO test. Either way any help on what to look for or what to change on the 126 and the 553 would be helpful.

Thanks in advanced.

 

Any help at all?

 

I would take the solenoid pack out of your old transmission and put it in the one you have now.
Also put your old computer back in the truck
Then see what happens now and what codes you get.

KOEO DTC 126 indicates the Manifold Absolute Pressure (MAP)/Barometric Pressure (BARO) sensor is out of Self-Test range. The correct MAP/BARO range is from 1.4 to 1.6 volts.

KOEO DTCs 553 and 552 indicate that voltage output for Secondary Air Injection solenoid(s) did not change when activated.

DTC 126 (KOER) indicates the MAP/BARO signal is out of range for Engine Running Self-Test.

 

Subford,
Thanks for your reply. I went out a few days after posting this and checked my wiring due to seeing some that had been eaten by mice. I had two wires that ran to the MAP sensor that had been eaten. I spliced those back together and the truck runs fine now. I had to change the computer because the old one was bad, or at least I changed them kept the trannys the same and it fixed my problems.
On another note I posted anther thread the other day about some wireing under my dash that I can't find out where it runs to. From looking around I have seen you have good knowledge of the wiring in these trucks. If you could take and look at that one and tell me what you think that would be greatly appreciated.
Thanks Dylan
Here is the link to the other thread: https://www.ford-trucks.com/forums/1...-the-dash.html

 

I saw that post and looked through the Ford 1989 shop manuals and found no such wire going through the dash. I did note that there was no grommet as it passes through the dash and that is always a sign to me that the wires may not be stock.

 

I can't find a single thing it might plug into. There is a grommet that it passes through might have been hard to see. It plugs into the wire harness so you wouldn't by chance know what that plug is for.

 

No I do not.
Can you post the wire colors at the plug?