ford 4.0 trans failure? AA wants comments

Hotweels · May 5, 2003

I will try and get a answer from him tonight or tommorow.... communications with him are VIA pm's on another web site so its kinda a hit and miss thing sometimes

Diff Whack Daddy · May 5, 2003

ALYZ1FLR, you have got to stop abbreviating. I have had way too many beers for that.. Remember, I'm Navy, that means I drink.

ie., 0.5 where? And yes, 94 was the changeover year, but your diagram still shows the pcm/eec sending a ground.

Hotweels · May 5, 2003

Just a bit more info, i think my man on the inside is haveing dinner

hehehe

Hey Dan, I remember some different electronics on the valve body depending on the year and model. I think the early gm stuff is power side switched, where the ford stuff is ground side switched, but we can work around that. I have overhaul manuals for the early 700R4's and the later 700R4s and 4L60's. I will check and let you know.

Diff Whack Daddy · May 5, 2003

Sweet, just the info we're looking for. Based on what I have seen, the 700-R4s are power side switched(12V), and the fords are ground side switched. Even according to the diagram ALYZ1FLR posted, it looks like the pcm sends a ground. I can make anything work, I just have to know how they work individualy before I can make them work together.

ALYZ1FLR · May 5, 2003

Look at the ammeter in this diagram.

Diff Whack Daddy · May 5, 2003

Okay, it's measuring the amps going through the circuit which is always where you measure amps, on the negative side of the circuit and inline. It still shows that a ground comes from "switch in the processor". Last I checked, the tranny has no processor so they have to be referring to the pcm/ecm. The best way to check is to put a multimeter to the coresponding wires and find out what is actually happening down there. I wish I had an Ex where I'm at because problems like this really get to me and I would hook up my wo multimeters to the wires nd go for a drive to figure it out.

Hotweels · May 5, 2003

Please dont let this start a fight guy's just keep in mind book's can be wrong sometimes.

I am not sure about the last part about the 94 being a change over year, the 4r55e did not happen until 95. I don't want to start a fight but if it would not set a code why does a code exist????? seee below
566b 3/4 shift solenoid 3/4 shift solenoid circuit fault KOEO 3/4 shift solenoid circuit failure. No 3-4, 4-3 shift. Refer to Pinpoint Test "A."
b Output circuit check, generated only by electrical conditions

Diff Whack Daddy · May 5, 2003

No fight here, just the minds of two, or more, people troubleshooting.

ALYZ1FLR · May 6, 2003

I only have the complete circuit

diagrams for 91 and 92 with expanations of ecm circuit functions. And it lists the trans. allow circuit 153 and 154 as allow or circuit complete only. And all previous material I have read does not show feed back until G.E.M.,s and R series transmisions. Switch in the processor refers to a mechanism that converts the ecm low voltage signal to a working voltage, Like a relay circuit. The ecm signal is to weak to actually function the servo on its own. This Isnt fighting this is constructive fun. I,m glad we have a place to discuss and learn. I hope I learn something from this.

ALYZ1FLR · May 6, 2003

Maybe the fault code stems from

a complete lack of circuit? That would be a totally diff. creature.

Diff Whack Daddy · May 6, 2003

Apparently there is a 25-40 ohm resistance in there somewhere. That is what the ecm measures. If it's not there, it turns on the dummy light. I am still researching it.

Diff Whack Daddy · May 6, 2003

Okay, ameters measure amperage. Therefore, when the ECM sends the ground to the 3-4 solenoid or the torque converter lockup solenoid, it completes a circuit, causin current flow witch causes amperage. The ECM may measure the amperage or it may just check to see if it's there period. With no amperage, that would mean you have an open circuit, maning the solenoid was bad or not there, ie. if you send a ground through an ope wire, there is no amperage. Once you connect that ground to a circuit, there is a current flow, causing amperage. This would explain why there is no feedback wire to the ECM from the tranny. To measure resistance, you would need a loop or a return wire back to the ECM. To measure amperage, you can do it inline.

Therefore, to fool the ECM, all we need is dummy circuit to replace the 3-4 shift solenoid. On the torque converter side, the relay converting the ground to 12V should provide that.

The question now is, does it actually measue the amperage and if so what amperage is it looking for, or does it just check to se if any amperage is present?

Hotweels · May 6, 2003

The question now is, does it actually measue the amperage and if so what amperage is it looking for, or does it just check to se if any amperage is present?

It is possible that ford buit in a ammeter to the ecm but highly doubtfull as production costs blah blah blah would be higher i will try and find out.

On the torque converter side, the relay converting the ground to 12V should provide that.

ok i think we need to clear this up, when there is no power to a 700r4 that means the converter is locked... right?
just like when you leave the connections off of a a4ld the converter will not lock.
Ford, no 12v to tcc = converter will not lock
Chev no 12v to tcc = converter will lock
does this make sense or am i missing something?

ALYZ1FLR · May 6, 2003

Diff Whack Daddy

Doo Wa Didee I think we got it D.W. I would say it checks for voltage present only. Because that ammeter in the diagram is listed as a trouble shooting visual aid. I will try it with a dummy circuit in the morning. Anyone want to guess what type of resistor I should use to get the same flow as the servo?

Hotweels · May 6, 2003

25-40 ohm resistor, go to yer local car sterio guy and ask for a 25 ohm tweeter resistor or try radio shack.

ALYZ1FLR · May 6, 2003

I,m rollin out to get one now!

Diff Whack Daddy · May 6, 2003

The 700-R4 tranny requires a 12V source that goes to a permanately grounded solenoid to lock the torque converter. The A4LD is opposite in that it sends a ground to a permanately powered (12V) solenoid. Think of the solenoid as a big relay. They always have a power or a ground but need both to energize it. It just depends on the engineer as to which one is sent.

ALYZ1FLR, I agree that it isn't an actual ameter with a needle and gauge and all, but a microcircuit can be set up in the ECM itself to look for a specific amperage. In the Navy I am a Sonar tech and our SONAR systtems that I work on have several of similar circuits for self diagnostics. And this is 70 technology I am working with.

Diff Whack Daddy · May 6, 2003

ALYZ1FLR, I am guessing on this one, but I would assume you would need two resistors. One for the torque converter solenoid and one for the 3-4 shift solenoid.

The way I GUESSING this works, is that the resistance between both solenoids + and - terminals is 26-40 ohms. That means, since the ECM sends a ground, the other end of the resistor would have to go to a 12V source. I STRESS THAT I AM GUESSIN as I don't want you to fry your ECM doing this.

As I stated before, I believe the PCM is looking for an amperage, or current through it's ground line that it sends to the tranny. If we use a 26-40 ohm resister to fool the PCM, one side of the resistor would go to the wire from the PCM, obviously. But since there is no wire returning to the PCM from the tranny, where would the other end of the resistor go? My GUESS is that the other end of the resistor would go to a continuous 12V source. However, that would show current on the circuit at all times, which may also confuse the PCM. Using the ground from the PCM to also energize a relay to send 12V to the other side of that resistor to allow for switching on and off. In other words, in the stock set up, it goes through the solenoid and then to a 12V continuous source. Current only there when ground is sent from PCM. I think the best way is to use the relay and resistor to simulte the solenoid, completing the circuit, providing a switched amperage to the ECM, effectively fooling the ECM.

Diff Whack Daddy · May 6, 2003

Sorry about that last post. I edited it to make the last paragraph to read correctly.

I am not good enough to design a relay circuit that would simate the solenoid to ensure the correct amperage reading, which looks like .5 amps(not sure on that one) without frying the PCM or electrical circuit. I am not sure a 26-40ohm resistor betwen the + and - side would be enough. Any electrical engineers out there?

Hotweels · May 7, 2003

Dude's.... i got info, PM me your e-mail addy's please.

ford 4.0 trans failure? AA wants comments

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

Attachments

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

Well-Known Member

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

And the Roll Over Posse! Under the Hood Moderator

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

And the Roll Over Posse! Under the Hood Moderator

And the Roll Over Posse! Under the Hood Moderator

And the Roll Over Posse! Under the Hood Moderator

Well-Known Member

Explorer Features

Explorer Features

Similar threads