A week ago I had written a post about a gearbox fault I received while on the highway. After reading some other posts regarding thus issue I realized that I failed to mention that it was raining when this happened. It looks like rain can sneak down the window and wet the plug on the computer causing funky problems. I looked at the plastic cowl on the window and the space is so large that you could practically see the cars computer, so water is definaty getting on it.
What can be done about this? Although I can't be sure that it is in fact water that caused my issue, I haven't had the gearbox fault return and it's been over a week. Also looking at the actual computer it appears that there is some play on the plastic cover. There is a large gold nut on the top, and when I grab that plastic piece I can wiggle it slightly as if that nut is loose.
Has anyone ever put a bead of silicone underneath the cowl to prevent water from dripping on it?

 

harryc, most guys remove the plug on the end of the computer and clean it up really good. Then they get some di-electric grease (non conductive kind) and then they put some inside the plug and then reinstall the plug. The grease will help prevent the water from entering the plug and causing ill effects from the pins getting shorted together. The grease has a very high resistance to it. Much higher than what water does.

 

Does removing the plug cause any issues itself like the computer forgetting settings and emissions?

 

harryc, yes, the TCM will loose any learned settings when you undo the plug. But, it will maintain a basic setting that will be more than adequate to get the learned settings back after a few miles on the road.

I personally recommend disconnecting the battery on the car with every oil change. What this does is force the car to re-learn how you drive. I have found that by doing this, your mileage will actually improve atleast for a short period of time and the car will be a little bit more responsive.

THink about it. You do not drive your car exactly the same way every day. Some days you do a lot of in town driving. Some days you get out on the highway and cruise. Some times you are easing up to speed. Then there are the days when you punch it to have a little fun. The computer is attempting to find a compromise between all these different ways that you drive. it is even worse if you have 2 or more drivers in the same vehicle.

 

Thermo, can you tell me how to remove the plug for the ecm unit under the hood? I removed both nuts from either end but still won't come off. Do you have to remove the star nut from the center? and if so, does it take a special socket?

 

Thermo, when I asked the guy at the auto parts store for non conductive di electric grease, he said their isnt such a grease, as its di-electric. What brand of grease were you talking about?

+1 about the ECM, need to clean the terminals from the windshield cowl lip not flush to the windshield, Just need some DIY directions, anyone?

 

Biggest giveaway from my standpoint. The big connector on the passenger side is only the engine management, not the transmission control module. My experience has found that some X-types do allow water onto the TCM. The ECM is just fine where and how it is for the most part. (At the dealer we saw more TCM concerns than ECM concerns with water infiltration).

The TCM is up under the left side kick panel to the left of your left foot (LHD) Right above it is the the hood release cable. This cable and its grommet are positioned just perfect to allow some water through and drip onto and into the TCM. It is somewhat difficult to get the TCM out to inspect but patience and a ten millimeter deep socket will help. If you car has auto-wipers then the module for that sits right on top of the TCM. Remove the lower ten mil. nut and tilt up the wiper module and pull down. There is a bent tab that engages the top and is tricky to get out. The TCM is held in by ten mil nuts top and bottom. remove them and remove the TCM. (make sure the battery is disconnected) Once you get it out you will be able to pry open the case and inspect for corrosion from water.
If it is corroded, then you can try cleaning off the board and the connectors. Dont forget to inspect the TCM connector!! There is probably some green in there as well. The above suggestions for the di-electric are still very good to help future concerns.

The water leak is usually caused by the hole for the release cable. Just get some good body urethane caulk and smear it all over the grommet and the wiring harness grommet from under the hood. This fixed most cars. Go inside and inspect to make sure the release cable grommet still has the ring pinching it closed inside. If not just use a couple zip ties to seal thing up.

We, at the dealer, spent many hours learning how to deal with that particular leak. We would actually lose money (flat rate) trying to figure these out but usually we were able to solve the water leaks. Give yourself some time to dissect that lower kick panel area and TCM to greatly reduce the leak or even eliminate it.

My suggestions are just from my experience and others may have different ideas and suggestions.

 

If you are going for a home remedy, open up what you can, and put the unit in a container of rice and shut the container up tight. Wait a few days, and things will usually dry out. I have saved one 350Z control unit on a flood car I bought, and my cell phone numerous times after washing it. I am kind of forgetful.....Be cool....Mike

 

Helpful video here