Trans Failsafe warnings after heavy rains

[m5james]

I'm still searching around at the moment, but I could have sworn I've seen posts in regards to gutter or something that allows the TCU to get wet, causing the TFS messages I've gotten a handful of times. I don't have a sunroof, but something is definately getting wet since that's the only time it happens.

Last time was a very distinct reaction of driving through heavy rain for 3+hrs, all was fine, then when I came off the offramp to Reno, BAM...TFS and the D light went out on the cluster. Stupidly I shut off the truck while I was cruising along on this road around 11pm at night and then it simply wouldn't even start, which is the second time this has happened after heavy rains. The trick I learned is to open the passenger door and jump on the doorjamb of the truck (which in my mind I feel is splashing/moving the water around) and then the truck finally starts, albeit in TFS mode still, but at least it starts.

I'm usually trying to answer other peoples questions, but this time I'm hoping maybe someone can throw me a bone since I don't remember the potential solution for this before I make the move back to SEAttle.

[Zulu95]

I remember reading about a potential problem with moisture and the wiring harness around the firewall causing this sporadically. I'm going back some so all the details are not as clear as they once were. I think it was to do with the drains being blocked and the water shorting a plug.
I had the problem once way back after sitting for 30 minutes in 95 degrees/100% humidity waiting for my wife. I pulled in and stopped and it cleared on the restart. There was a big puddle of water where we stopped so I guess the system was over come by the condensation.

[m5james]

Yeah, I remember reading something about someone removing the ECU and the contacts had waterspotting and rust on them, so I guess I'll have to get off my butt and look into doing that.

[m5james]

So I'm back to living in crappy, rainy Seattle due to a job relocation. Once again, I'm also experiencing the same TFS (trans failsafe) errors today, w/ today being the oddest of the all. As it's happened in the past, driving down the road, everything is fine, come off the freeway off ramp to a stop, and BAM...error message, D light is out on the dash and I'm only driving in 3rd gear. This time the cluster looked like a light show....flashing back and forth from D, S3, S4, back to blank and OBC error, P turning on and off as I sit parked. Clearly something is getting wet and water is moving forward due to the momentum of braking to a stop, turning, etc so I'm pretty sure I can rule out wheel sensors since it only happens when I come to a stop. Between my Peake tool and OBDII bluetooth/Torque app on my phone, both just give me random P codes that relate to things failing in the trans.

Since this ONLY happens on heavy rains, I'm going to discount these codes to whatever is getting wet and causing the TFS issue in the 1st place. As I had mentioned earlier, I dont have a sunroof, so does ANY know (I dont) where the transmission computer is and/or have suggestions of places to look where water could be puddling and causing electrical issue. It's not be a battery or an alternator issue since this happens in specific situations (heavy rain, coming to a stop) and goes away once the weather clears.

[m5james]

Just for an update, I'm not experiencing the same TFS messages, but now Sport mode doesnt work at all. If and only when coming from a complete stop, it skips S and D showing, and immediately jumps to M1. Bumping the shifter + or - does nothing, starting in M1 it will continue shifting to M2 and M3 if I go fast enough, but its a forced shift by default after going all the way to redline.

Based on another suggestion from threads I'd read a year or so ago when this first started, I've already pulled and cleaned the gear indicator switch on the side of the transmission, but who knows if it's still not an issue as well.

I have yet to find the ECU/TCM to make sure they're not getting wet, and hopefully within a week or so i'll have my laptop back w/ its new image up & running so I can read deeper into the engine codes. Wish me luck.

[thedweeb]

Open the hood, top right hand corner theres a black box. In there you will find your ecu and tcm.
Dweeb

[m5james]

Thanks, Dweeb....that just sounds wrong saying that I knew the ECU was there because thats where I've spliced into the wiring to power my angel eyes kit to run w/ the interior lights and/or when the ignition is on, I just havent gotten the time to yank the cover since its been so damn cold outside. Come to think of it, I should just pull the cover and then set a low heat hairdryer in there one of these nights just for the hell of it to see if everything comes back on in the meantime. If the problem is solved the next morning, then i'll know 100% for sure what my issue is.

[ienjoydrifting]

Also,

The connector that is on the side of the trans pan probably needs to be cleaned.

Had the same issue a few months ago. Cleaned the connections inside the connector and put some dyelectric grease on there and I was good to go.

[m5james]

I havent been under there in months, so which connector are you referring to? I was thinking di-electic grease as well since it'd be a good way to have something filling those cavities or air in an attempt to keep any water out.

[m5james]

Yanked both computers tonight, and while the ECU looks fine, the TCM looks a little worse in the corrosion department. I'll be going to Radio Shack first thing in the morning for some electronic parts cleaner before brushing on a light film of di-electric grease to prevent this in the future. I've really got my fingers crossed that cleaning off this white crust will solve some my issues.

Now that I see how deep the area is that stores the ECU and TCM, clearly puddling water isn't the issue, so now I've got that to figure out where water could be causing issues since (on more than one occasion) I've driven on road trips to only have the TFS message pop-up immediately after coming to a stop.