tcm problems with mercury villager 98

Damaged TCM for the 3rd time

The TCM has failed again for the third time in the past two years. I have 130,000 km on the van.

Can anyone tell me if this is a known problem on the Nissan transmission and if there is anytime I can do to prevent this problem again?

It cost me $1,000 cdn (this is using a rebuilt TCM - a brand new TCM cost more than a $1,000) everytime I change the TCM.

Thanks!

What is a TCM?

A TCM is a Transmission Control Module. It is a computer that does similar function as the ECM but stricly for the transmission. It receives signals from different sensors and uses that to signal to the transmission when to shift gear from 1 to 2nd and from 2 to 3rd gear. The TCM being defective, the transmission shifting between 1 2 and 3rd gear is not smooth at all (it's like a big knock) unless you release the gas pedal completely and let it change smoothly then.

The TCM is a small 4 X 4 inch. square box (1 inch thick) that sits just above the steering column under the dash board. It is fairly easy to replace.

Of all the research and talks to different dealers that I did, I have been told that part rarely fails on the Villager. So there is something that makes it fails on my van.

Have you checked your TPS sensor? I had mine replaced becuase of idle up/down surging etc. It also turns out to be waht sends a seignal to the tranny that the gears need to change. Give the local dealer a visit for a check up about $100 or lower. I do not like to visit the dealer but after replacing the TPS myself and having it fail. I paid them $450 Total. That price included the check and the emissons cleaning that they also did.

Please excuse the ignorance but what is a TPS sensor? Do you think it will cause surging idle only when the engine is cold? Thanks.

Yes both cold an hot
TPS Throttle position sensor. It controls fuel delivery and idle postion

The TCM has failed again for the third time in the past two years.
After it was replaced did the trans shift smoothly again?

I would bet that the mechanics disconnected the battry to change the TCM...When they do that they erase the codes and evry shift pattern the TCM knows.

When they replaced the TCM, (How do you know they really did or not, unless you put a recognizabale mark on the old one to prove it) the shift patters need to relaerned by driving around for a while.

If their is a faulty sensor you would get a flash on your OD light when you first put the key in and turn it before starting the engine. :naughty:

The TCM is a small 4 X 4 inch. square box (1 inch thick) that sits just above the steering column under the dash board. It is fairly easy to replaceagain?


Has anyone changed theirs on a 1995 Villager? Is it located in the same place as the 1998 models?

I may have the same problem on my 1995. I checked everything including VSS, TPS ...all looked good. I know of a later model villager in a junk yard...maybe I can grab the TCM and try repalcing mine to see if that coreects the shifting problem..

3 times in 2 years..and at 1000 bucks a crack! man thats hwy robery!!!

It almost tells you how frequent these things fail.

Did you have to pay 1000 bucks each time? If so..You would have been better off getting a new one right from the start...you aleady paid 3000 bucks for nothing... Jeeze thanks for that lesson. I would go down to that dealer with a mouthful of bad language, if you know what I mean!

I am a firm believer of NEVER buying or replacing any electrical part unless Its NEW or I can get used parts for FREE or very cheap. This story is a very good testimont to that!!!

I had exactly the same problem on my '93. The dealer replaced the TCM twice and it failed again. The problem turned out to be be that they were curing the symptom rather than the cause!

The real problem is that the ground strap from the engine/transaxle to the frame is inadequate (this is a known problem). After a while this provides too much resistance causing the voltage of the whole assembly to go up and excess ground current is shunted through the TCM causing it to burn out. If you open up the metal TCM box you can see the burned ground traces on the PCB.

I solved the problem by adding a secondary ground strap directly from the battery to the engine.

Hope this helps.
Steve

Hey Steve,

Sounds like Mercury has a problem but never put out a service note or tech note about it.

I had done some circuit repairs before.

When you looked at burned traces do they look fixable?

Solder Iron with some wire to repair traces?

I want to check mine now to see if I got the same problem. Hmmm. MAkes me think now, I remember several years ago while driving the vehicle i thought I smelled something burning. I thuoght it came from the outside. Seems like the smell was something electronic burning, like a transistor going bad. ?(I know what that smells like!) I'll Bet it was the TCM burning up!

I'll have to take a look!

Thanks for the valuable Info!!!!

No, I tried to fix it by soldering on wire jumpers over the burned area but to no avail. It was a long shot since there was a lot of damage and it was unlikely something else didn't cooked.

Although the grounding problem was known (apparently to Ford as well), it probably occurs far more frequently in high salt areas. Although I never checked, supposedly the strap just goes to the dip-stick tube.

Luckily I checked on the internet before replacing it last time otherwise the dealer would have probably just kept swapping them. "Duh, the computer says the TCM is gone again. Better put in another one..." (I wonder how many times this would have gone on?)

Cheers.
Steve

Luckily I checked on the internet before replacing it last time otherwise the dealer would have probably just kept swapping them. "Duh, the computer says the TCM is gone again. Better put in another one..." (I wonder how many times this would have gone on?)

Cheers.
Steve

Hey Steve,

What website did you find this info on???

Seems like a good one... :lol2:

Good question! It was a couple of years ago and I can't remember for sure.
I'm pretty sure I got the info from dejanews, but it seems to have been taken over by Google. When I put in the appropriate keywords there though it doesn't come up - go figure.

If I can relocate it I'll let you know.
Steve

http://www.automotiveforums.com/t196775.html
Related story.