a604 Limp, Rebuilt, Sensors replaced, solenoid replaced still Limps!

helt klart är det fel inne i lådan..sitter en kona som är
fjäderbelastad med gummitätning som gått åt helsike ..ta ned lådan
själv..och öppna den..är skitlätt!! vill du ha steg för steg
hjälp så hör av dig på detta forum

 

Yes the address is valid. I own the domain so I setup this temporary
address so I could post with a valid email addy to the newsgroups.

Well if the DC dealer can be believed my current TCM is flashed up to
latest now. Since I got the car back from them it has tried to go into
limp on me but only when I put it in drive and when its in overdrive.
If I drive th car in 3rd on the gearshift indicator it will not go
into limp.

Waiting on the trans shop now to finish prepping a new tranny as soon
as its ready they get the car for a day.

 

Just dropped in on this thread and I'm surprised it's still going on.

I doubt that another transmission will fix this. The whole thing smells
like a control problem, just like the one I had. I'll say it again -
it's either in the wiring harness connectors, or in one of the control
modules. You might change the TCM or whatever and find the problem
gone. While it could have been the module, it also could be the
connectors on the module. Sometimes the very act of removing the
connector and then re-installing it will make a problem disappear (which
tells you where the problem is).

In the line of work I'm in , we see it frequently enough : a $500K UPS
stops working properly because of one bad crimp on one pin in one
connector on a ribbon cable (and there nearly 20 ribbon cables).

Phil

 

That might be worth the few minutes...Get a can of contact cleaner
that is safe for plastics. Disconnect the TCM (I believe it is an 8mm
socket) harness. Pull the harness off, and spray the harness down to
remove any debris. Take a few minutes to let the harness dry, and
inspect the connections. If possible, remove the cover that covers the
back of the harness, and look for a possible pinched or broken wire.

I will try to get a copy of those two pages for you ASAP. I am waiting
for a part to fix my server so I can print and scan again.

 

For anyone else that wants it......

TCM and Solenoid pinous....

 

Just a quick update. I had the car back in the trans shop for a week
while i was laid up with surgery. It had been perfoming 100% normal in
3 but if i put it in D it would go into limp. The trans shop worked on
it and when I went to pick it up (free of charge as its under
warranty) they smiled and said drive it a few weeks and let us know
how it goes and we will tell you what we did. Well I drove it for 3
weeks and no problems and no limp! I was amazed so I called back and
they told me that all they had done was unhook the computer and spray
a ton of contact cleaner on the cable contacts. I was floored but
happy, until yesterday, it went into limp again. So now I'm trying to
decide what to do next. I may order the harness from Dodge or I may
try some contact enhancer like DeOxIt Gold or
http://www.napaonline.com/MasterPag...Number=CE1&Description=Contact+Enhancer+Fluid
which gets great reccomendations.

 

Hate to jump in so late, but did you try changing the "saftey shut down
relay" AKA the "EATX relay"?
Worn or corroded contacts on this relay will cause intermittent limp in
as was told to me by a Dodge service tech when I had the same problem
you have. He said that's the first thing he would change in a "Mystery
Scenario" and there's a fair chance it would fix the problem. They cost
about 20 bucks.

 

Aha, so that's the stuff. When I wrote my last post above I mentioned
something that cost $22. Well, that stuff from Napa is Stabilant 22A,
so I probably confused the 22 with the numbers in the title for the
cost. About the cost, it's now $72.

20 years ago, when I ran across this stuff, it was around $25. Must be
good stuff to last all these years, that's a lot of years and no name
change. According to the web site, www.stabilant.com, it was product of
the year in Jerry Pournelle's column for Byte magazine, in 1985.

I guess the price was too high. I do use isopropyl alcohol a lot and
Stabilant 22A is 80% alcohol and 20% their special chemical. It's
spelled out in their MSDS sheet.

Did the tranny shop say what specifically they used to clean the
contact cleaners? The above expensive stuff or Radio Shack or what?

Did they try what the next post suggested?

What do you think? A marginal connection or component or resistor that
meets specs when you lower the connectivity resistance. Have you tried
the suggestion from the next post about the safety limp mode system?

 

I use the DeoxIT stuff. So much easier to use than Stabilant and for me
works so much better.
Plus there are many convenient applicators to use. Many of the auto
companies spec it in - as the ONLY thing to use.
Good enough for me. I don't use anything else. Another plus - cost
much less than Stabilant.
www.caig.com

Mike

 

Well time to ressurect this thread even though I would like to burry
the car.

In October the shop rebuilt the transmission for the 4th time and then
they put their foot down and told me they wanted to find the problem
and didnt want to release the car to me till they did so. After a few
days they called and said it needed a new TCU so I went and picked the
core up from them and took it to Dodge and obtained a replacement.
After the trans shop installed the new TCU the car was fine until
yesterday.

Yesterday I am on my way home on the freeway and the speedometer
starts dropping speed and then jumping back up while I was maintaining
a constant speed. When I took my normal offramp to come home it
dropped into limp and stayed there despite shutting the car off and
trying to drive it and also trying to drive it in 3rd which had worked
prior to the last in shop repair.

So I took a guess that the output speed sensor had crapped out and got
a new Bosch unit and put it in, no change. When you drive it the
speedometer needle is all over the map and it stays in limp.

Any thoughts or suggestions?

 

Did you pull the trouble codes from the TCM? That's the first thing you do
when troubleshooting an A-604. Could even be a bad wire.

 

Did Dodge keep the core of the TCU? Maybe you can swap it back in
as a test?

Sounds like a bad electrical connector somewhere to me. Take apart all the
connectors
and if there's water in any of them then spray WD40 in them. Go to Lowes
and
they sella bottle of electrical conductive grease, put a tiny dab of this on
each contact
and reassemble the connectors. Do this with every electrical contact on the
transmission and harness to the TCU.

On this transmission the fluid lines are above the sensors and fluid leaks
will
come down right on the sensors, and soften the rubber that holds the
contacts.
The contact design itself in the sensor also sucks rocks.

Also make sure your body grounds are good, the TCU is grounded, etc.

Ted

 

I agree with your diagnosis of the output speed sensor this time around.
I've never used Bosch sensors since I had trouble with Bosch plugs once so
stay away from their components unless there is no other alternative. You
say the trans has been rebuilt 4 times, but did it actually require this
action each time or is this just showing the limitations of the shop you
have chosen?

Some suggestions to consider:

Weak/dying battery, resistive electrical connections, bad/poor ground to
TCU, bad connector at the output speed sensor, defective wiring to the
sensor, etc.

Good luck.

Bob

 

The codes have been worthless in the past always pointing to a bad speed
sensor and there were both replaced several times and their harness gone
over. That said I would normally have gotten the codes pulled in short
order but the car crudded out on me on friday on the way home from work
and I never had a chance to get it to the shop before they closed for the
weekend.

 

Yep, was something like a $85 core charge besides the chip directly under
the inspection plug on the cover was cooked as was all the potting
material over the chip.

I may try this again, its been done numerous times, the last time I used
DeOxIt and their gold contact enhancer. Didnt help at all.

Thanks Ted, this transmission is an example of how not to design a
transmission from the cruddy sensors, to the sheer number of TSB's to the
very sub par electronics...

Grounds are good, and there is a ground directly from the bellhousing
directly to the "Jump Start" negative terminal.

 

Not sure if its their limitation or just the fact that the bloody thing is
so intermittent when it fails and the computer diag is worthless well....
I dunno the shop has tried I will give them that.

All I can think is a wiring gremlin, but Dodge wasnt ever able to find it
either. All said and done this transmission failure has cost me more than
the car did. I filed a NHTSA report on this last night. Here is the body
of it.

Your Confirmation number (ODI Number) is: 10177406

Complaint Information
Description : Purchased vehicle with clean CARFAX record in Feb 06
with 75k Miles. At 81K miles transmission started going into limp
mode(slams into second gear regardless of vehicle speed). Took car to
dealership for diagnostic. They stated the input and output speed
sensors were failing according to the computer. I replaced them. A week
later the transmission fully failed. Towed to a reputable transmission
chain store. They fully rebuilt the mechanicals of transmission and
replaced the speed sensors again. As I drove home the transmission
returned to limp mode. Returned to shop. They test drove it and second
gear clutches burned up. They rebuilt it again and also replaced valve
body and solenoid pack. I drove the car for a month before it again
started limping. Took the car to another dealership for diagnosis. They
blamed the shop and stated they couldn't do anything for me but upgrade
the flash in the transmission computer. The computer diagnostics could
not reveal why the computer was putting the car in limp. Returned car to
previous transmission shop for yet another rebuild. Drove car 2 months
before it again started limping. Returned car to trans shop, they
rebuilt it again. Still couldn't find concrete cause, replaced valve
body again, had me buy replacement transmission computer from Dodge,
this fixed it for another 2 months. yesterday it again started going
into limp. There is 200 miles remaining in the 12,000 mile rebuild
warranty from the first rebuild so it will be in the shop for the 5th
time in less than a year.

 

If the computer keeps throwing a code for the speed sensors you are going to
have to put a oscilloscope on the speed sensor output and check it to see
that your getting a solid signal. Then run the vehicle on the highway for
an hour and come back to the garage and let it idle for 20-30 minutes to
get it really good and hot, and then recheck both input and output speed
sensors output with the scope.

Ted

 

An oscilloscope!!What's that!!??

More horse and buggy thinking.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I think it's function F9 on the $5K chrysler scanner but since few of the
techs know how to use one anymore, I couldn't tell you. ;-)

Sigh. I know. Just too hard for me to give up methods that work, you know.
;-)

Ted

 

Heh,

It's not just the design, it's the implementation. For example, take the
input speed sensors. The original ones were brass. Later the vendor that
made then switched to plastic. Lots more sensor failure complaints then.
The theory is the plastic does not conduct heat into the body of the
transmission
as readily, so the chip inside the sensor fails due to overheating.

Ted