E4od woes code 29

[cowman79]

So i decided to drive my truck to work today and about 10 miles into my drive the torque converter unlocked for about 5 seconds and then about two miles down the road it unlocked again for a couple of miles. Then the OD light quit flashing and the truck stayed in limp mode. I pulled the codes when I got home to day and I had a code 23 TPS out of range A code 1 which I thought was weird and lastly a code 29 VSS. I just installed a new ford speed sensor about a month and a half ago. Also when the truck started acting up today the speedometer never bobbled not once. This is what I don't understand because even though it is throwing a VSS code why isn't the speedometer bouncing. Any help would be greatly appreciated. I installed my spare transmission computer and I will try that for a while and see what happens.


edit

Also this transmission has only been installed for about a week and only has about 150 miles on it. I have also had this code with the previous transmission. That is why I installed a new OEM sensor.

 

[LCAM-01XA]

Do you have cruise control on this truck? If yes does it work while the OD light is flashing and the TCM is in limp mode?

Reason for asking is because both the TCM and the cruise brain are fed the same signal. Which is actually different from the signal the VSS provides. Basically the "raw" VSS signal is fed into the ABS brain and the PSOM. ABS uses it as is, PSOM converts it to 8000 pulses/mile and sends it to cruise and TCM. So if ABS works then VSS is good. And if cruise misbehaves together with TCM then that sould suggest an issue with the signal converting device (the PSOM).

I'm not entirely sure what signal the speedometer gauge uses, but I think it's the "raw" signal from the VSS and not the "processed" signal from the PSOM. Which would also explain how you're getting good gauge reading but crappy TCM operation.

Look here:
http://www.supermotors.net/registry/media/95932_1

 

[cowman79]

I do have cruise But it has never worked. When I bought the truck the fuse was blown for the cruise control. I replaced the fuse for the cruise control and the cruise never worked so I just left it alone because I didnt want to buy a new module or troubleshoot the cruise problem.

 

[cowman79]

I have been looking for a good manual that has the actual wiring diagram for the whole truck so that troubleshooting would be easier but they seems to be hard to find.

 

[LCAM-01XA]

What you need is a factory manual. There are 2 kinds, the shop manual and the EVTM. The shop manual is nice to have, but for what you want the EVTM will serve you better IMHO. I just did a quick search on evilbay and it came out dry as martini, at least as far as 1994 trucks are concerned. Keep checking periodically and you'll find one eventually.

 

[icanfixall]

So when was the last time the tps on the injection pump was replaced. They require replacement about every 75,000 miles. The wire field that the pointer rubs on wears out. Then you get intermitend signals. Then the trans goes to limp home mode. Wram up the engine and check the center wire on the drivers side of the tps. At idle it should be .96 to 1.2 volts key on engine off. If its an old tps change it. If its fairly new adjust it. Do it witha trusting digital voltometer.

 

[LCAM-01XA]

Icanfixall, if you're going by his "TPS out of range" code #23, that's likely cause he didn't have the throttle floored. I sometimes forget to do it mine as well, which is nothing compared to when I forget to release it after I'm done and go to start the engine with the hand throttle still set to wide open

Good advice regardless, and btw that contacts wear is the same issue that kills fuel level senders...

 

[gandalf]

I have a cruise control diagnostic which I'd be happy to send along to you if you'd like. It doesn't say specifically what year(s) it covers, but it may help.

It's a 30 Kb M$ Word document. If you'd like a copy, PM me with your email address and I'll get it off to you.

 

[cowman79]

That cruise control diagnostic would be great.

 

[icanfixall]

This is true about the fuel gauges in the tanks. The constant sliding of the contacts wears off the wires. Then its too bad. Sure is an old idea. Wish someone here would dream up a new design so we can have accurate gauges for once.

 

[cowman79]

Thats tps is only about two yours and 10000 miles old and it is a oem sensor and I forgot to hold the pedal to the floor when doing the diagnostic

 

[cowman79]

I removed the instrument cluster and checked all connections. Everything seemed to be in good shape. I reset the codes and will test drive tomorrow. I was wondering if there is anyway to view the signal that the TCM is seeing. I don't mind spending the money on a PSOM but I would like to know for sure if it is good or bad.

 

[LCAM-01XA]

Icanfixall, the better design fuel level senders are already out there. Capacitance is what they run on IIRC. Mucho dinero tho.

Cowman, then don't worry about the TPS. On that link I gave you Steve83 says you can test the signal coming in from your VSS by measuring voltage and frequency between its wires at pins #4 and #5. The same method may be applicable to test PSOM output, between pins #7 (signal) and #2 (ground). 8000 pulses per mile at 30 mph are 240,000 pulses per hour, which translates to about 67Hz - that would be measurable with a frequency counter or an osciloscope. I'm sure there will be some voltage as well, tho I have no idea what that would be - I'm thinking that since the entire cluster operates on 5V reference voltage the 3.5V given for the VSS test may still apply. One way to find out I guess.

 

[LCAM-01XA]

Oh, the wire carrying speed signal to the TCM is grey/black in color, and connects to pin #3 of the TCM connector. When you pull the TCM connector one of the 4 outer corner pins will have a fat plastic indexing tab/tooth right next to it, this is pin #60. Pin #1 will be clear across it in the diagonally opposite corner. Pin #3 is two pins down from pin #1, going along the long side of the connector. So just look for a grey/black wire 3 pins away from the connector corner that does not have the fat indexing tab/tooth on the outside of it.