i hope someone can figure out wtf is going on here. i can't get my truck to lock up in overdrive. i can putz around in overdrive, but when i climb a hill with the cruise on, or i open up the throtle my truck revs up to 4 grand and won't lock up. i've taken the thing to the tranny shop. the tranny shop says the tranny is fine.

i replaced the pmd back in march. however i never installed a restristor, i recently purchased a #9 resistor. my check engine light has been on ever since i installed the new pmd, the tranny started acting up a week later.

so far i've tried a new fuel filter,ops,#9 resistor,lift pump,fuelpump relay.

Make sure you have good volt reading. The trans likes to see damn near 14 volts. After that it could be dirty electric connector plugs. That's assuming the trans indeed checks out ok.
Ted

Make sure the brake switch is adjusted properly....if it is off a bit it won't let the TCC lock...

how do i adjust the brake switch??? just make sure the light isn't coming on???

if my brake switch is bad, would my cruise control still work??????

Address the SES lite, first - most of the rest will then heal itself...............

Address the SES lite, first - most of the rest will then heal itself...............

I'm with gmctd... the PCM reacts funny to trouble situations. Some things go into limp mode and just don't come back until the original problem is fixed. Sort of like a bad PMD will trigger an event that disconnects cruise control, and you can't get it back on until you re-start and the codes clear.

Now, here's a question for you tech-types: if greg here installed a pmd with no resistor, and the thing coded, it should mean that the PCM lost the stored value from the old resistor, correct?

He has OBD-II. If he then finally replaced the resistor with a #9, the pcm shouldn't pick up that value without a re-learn, right?

If the SES light is still on, he's still in the situation he got into when he put in the PMD and lost the stored value... solution should be to do a re-learn? Can he just do the ko-ko thing with an OBD-II?

i just noticed that i don't have any brake lights, maybe i will get lucky with a new brake switch!!!!!!

i just noticed that i don't have any brake lights, maybe i will get lucky with a new brake switch!!!!!!


Well, you might get lucky, but it won't fix your TCC lockup issue, unless your earlier comment about cruise control meant that your cruise control was also dead.

Fixing the break light issue won't make the SES light go out, either.

On the Fords, when a brake switch goes bad, the vehicle cannot be taken out of Park. The cruise control will not function also.

You are started in the right direction, but you still need to address the SES light.

Replace brake switch....bad switch = no TCC lockup

Fortunately, replacing the brake switch will cure the TCC problem, and cruise, and some other stuff - and the switch is non-adjustable.

Brakelites, TCC, and cruise are all nested in that rectangular plastic module at the top of your brake pedal arm, with several wires in the connector - non-operable brakelites are a good clue to required replacement.

And, yes - ko-ko will pickup the FSD resistor value

and the switch is non-adjustable.



What year did that change?

I have had to adjust brake switches on these OBS trucks up to '91 - there is a little lever that you move while someone watches the brake lights - haven't had to touch them on anything newer than that though...

excuse my ignorance here, but what is the ko-ko????

'94 OBD trucks got the new switches, when cruise went to PCM with drive-by-wire.

Key on key off routine, in FAQ's - resets PCM, relearns timing in OBD2 '96-up systems

I had the same problem, and i found it to be the boost sensor went out and the truck would go into limp mode when ever i got over approximately 5 psi of boost. i replaced the boost sensor and all was fine again.

i replaced the brake switch today. the first couple of times i got on it, the conventor never locked up. then it started to lock-up again. i seemed to worked better when i smashed the throtle. maybe it'll come out of it:cool:

So......fixed?

no i guess its not fixed:( . now when i accelerate normally it won't lockup. if i put it to the floor it does lockup, but its not pulling as hard as it use to. i'll try a boost sensor tommorro if i get time.

Engine coolant Temperature is another part of the puzzle before the ECM allows the TCC to lockup.

What code did you have in the computer anyway? WOT does not equal lockup.