trans trouble

[trugertha1]

hey everyone im lost on my trans problem, thought it was the comp no go...so here it is, i cannot turn off my o/d, light will not come on...the truck only has second and o/d, and if i don't put it in 2nd then it will always be in o/d...tach does not work anymore, replaced rpm sensor(with used one) no go..filp does not show any voltage anymore.. so im lost, any ideas will be greatly appreciated..thanx

 

[LCAM-01XA]

Oh boy, aren't you in deep mess. IIRC the FIPL and OD switch are both powered through the PCM, so if that's dead or not getting any power to it to begin with neither of those two things will work. The tach sender I believe was key-on power through the dash harness, and the PCM reads it but don't power it, but I ain't too sure on that one. Have you checked the TECA relay on the left fender behind the washer and overflow bottles? If that's dead the PCM will have no power, and you'll be experiencing what you have now - which by the way is the factory full-hydraulic controlled limp mode, designed so that even if your harness falls off the trans you can still make it home.

 

[trugertha1]

thanx for another coming back for another round of fun haha
so the black box type thing behind the washer fluid is a bank of relays?
guess the rpm sensor i got is used so it could be roasted as well..can i check the sensor
i switch the pcm with one from a used truck no difference
im gunna check those relays...anyway to see if their blown?

 

[LCAM-01XA]

For the relays have someone turn the ignition on (without actually starting the engine) while you stay right next to the relays and listen good, should be able to hear a click when the key hits "run" position. Watch out tho, cause about the same time the glowplugs controller will energize its own relay, and that one is pretty darn loud, ignore that loud click and listen for a light click coming from the black box on the fender. Should be just one relay there actually, unless you have factory tow package, but I don't thing you do.

You can also test the relay by pulling it and attaching jumper wires to it, but I can't tell ya exactly which terminals need jumped for that as Ford has some quite random relay setups and I dunno which is which.

 

[Andylad13]

That relay was the problem for me about a year ago or so. It blew and a new one from ford is $20.00. Its very simple to test, there is a big wire going to it and from it (in addition to the other 2 wires I beleive) When you turn the truck on, the 2 leads going into the connector with the relay installed should have power, if the one that doesn't have power going to it when the truck is off still doesn't have power when the truck is on, the relay is junk.

Here's another test too, when mine was acting up I tried to get a OBDI code from it, turns out that when the "pcm power relay" doesn't work, (which is the name of that relay) guess what else doesn't. So if you can't pull codes from it and it acts like the scanner is broke, it's definatly the relay.

Check the relay first, don't mess around with anything else until you know the relay is good. I doubt all these things crapped out all at once.

 

[trugertha1]

ITS FIXED, ITS FIXED!!!!! haha, new pcm combined with a relay and some wiring, did the trick...thanx a million!

 

[LCAM-01XA]

Sweetness!!! What wiring did you have to do? If you want a bit firmer shifts I still have the TransGo kit springs from my transmission... By the way, are you sure the PCM is indeed dead? Did you try running it with the new relay?

 

[trugertha1]

theres 2 yellow wires going into the pcm relay, they were all cracked and exposed replaced, new relay, no good, try new pcm, old relay and wiring works great now...how do you like your trans go setup, and what was the cost?