Hello all,

It has been awhile since I have visited these forums, but I am in desperate need of assistance. Yesterday, while riding on the highway, I went to accelerate and my truck down-shifted rather harshly. Afterwards, my truck proceeded to stall, so I pulled over on the side of the road. I managed to get the truck restarted and it seemed to idle fine; my check engine light came on though. Trying to put the truck into either drive or reverse resulted in a bang, and accelerating causes the truck to shift extremely hard. Getting it towed back to the house was my only option. It also wants to stall intermittently when I try to put it into gear.

I have attempted to pull codes for my truck, and I came up with: 26 and 126

From what I have read, 126 indicates a bad MAP sensor, and 26 could indicate MAF sensor being out of range. These may affect how the engines runs, but would either affect how the transmission operates?

I am hoping that someone has some advice that they could offer, because at this time, my vehicle is not drivable; I depend on it to get to work, as I know most of you do with your vehicles. I do most all of the maintenance on my truck myself, and don't have a problem getting my hands dirty. However, this is an issue that I do not know how to readily solve. Any assistance would be greatly appreciated.

My truck is a 1995 XL, 300, with E4OD

 

Well, one thing here is, you will either have 2 digit or 3 digit codes, never both!!

As the E4OD is completely computer controlled, any fault code can cause the E4OD to go into limp mode..

 

Is there any way for my truck to tell exactly which of the two I should be pulling? Noted. I will have to go back out there and try to read them again.

 

I'm just guessing on the year it changed but I am thinking yours "should" be 3 digits...

 

I went ahead and warmed the engine and pulled the codes again. The only code that appeared was 126.

I found a broken vacuum line that I fixed. I was able to drive my truck a few miles to warm the engine. The only symptom that I am experiencing is extremely hard shifts. It does go through every gear however.

Any suggestions?

 

Does the speedo operate normally?

 

Yes, the speedometer does work normally, as does the tach. Here is something interesting/concerning.

I just performed an engine running test, and I came up with the code "998."

998: Engine Control Module (ECM) - Hard fault present

Now. I have performed this test three times now to make sure that I wasn't mistaken. The two codes that are present on my truck are:

126
998

The 998 code is a bit disconcerting. Could this mean that the ECM is bad?

 

This is most likely your problem, the computer is programmed to switch to a "safe" strategy when any one of the major sensors develops a fault and part of that strategy is to jack transmission line pressure to maximum which results in very hard shifts. Note.. there is no MAP/Baro sensor on a MAF truck, that info is calculated using MAF sensor data, and that implies that you have a MAF sensor fault.

 

For those wondering, the issue was a faulty MAP sensor, causing the vehicle to go into limp mode.

Here is the thread that helped me to fix my truck: '92 F150; Rearended now Hardshift : Codes 126 & 998 HELP - F150online Forums

Thank you everyone for assisting me. My truck is now running as it should. Now if I could only save the money to replace tie rod ends, radius arm bushings, and shocks. lol

 

Glad to hear it's been sorted.

One thing about hard shifts on the E4OD: while it's uncomfortable, at least you're not wearing the transmission out. It's probably not generating much heat at all. No; those extra-crisp shifts are hammering on the U-joints and rear gears.

Pretty hard to drive when that happens!

 

My stupid e4od hard shifted and wouldn't engage 4th... even after a $3200 rebuild. My speedo/PSOM is the culprit... I tested my theory by banging the dash with my fist and now it shifts like normal...