Intermittent trans failsafe message
 

Before anyone offers the "use the search tool" answer, let me say that I've read through 4 or 5 threads covering similar issues and none of them were quite like mine. That being out of the way, my situation is as follows.

after cresting a sharp hill, I drove through a long deep puddle at about 50 mph. It was unavoidable(the puddle stretched across both lanes and filled the ditches) and there wasn't enough room, between the crest of the hill and the beginning of the puddle to shave any real speed, so I was along for the ride.

About mid-way through, the engine died and I coasted it onto the side of the road. The engine didn't suck water thankfully, but the dme got drenched and the car needed a few days, to dry out. Once the dme dried out, I discovered that the battery died, so I trickled that to full strength, cleaned out as many electrical connections as I thought were relevant, in the engine bay and she fired right up, no problem.

This brings us to the current problem, which is that despite the battery being 100% charged and in good health and the charging system testing out as good; I have an intermittent trans failsafe message displaying. Strangely though, the vehicle has worked fine twice, without displaying the message, but re-displayed it after and every day since.

my question now is, if the charging system is healthy and I know that the battery is fine and fully charged, what else might cause this problem? At first I thought that the tcm just needed more time to dry out, but with the problem returning after randomly going away, I no longer think that's it.

I should probably mention that it will go into failsafe mode, regardless of how recently I drove it, what time of day it is, weather I'm manually shifting or not and regardless of how slowly, I feed in throttle input.

If any of you have had a similar experience, please share your results!

Must have been a pretty deep puddle to shut off the engine. You probably have some bad contacts that the water is still present in. May have to disconnect a few harnesses by the tranny to see what you have. How high was the water?

It was likely over a foot deep, in the deepest part and 50-60 feet long; more of a pond on the road, really. The dme/tcm box, got saturated; I have no idea how it didn't also suck water.

Did you get the X scan for any code in the TCM? Even if the Trans Fail goes away after a restart, you might have a code logged into memory. That will at least tell you why the trans is going into fail safe mode.

Working on that. The code reader at the local parts stores couldn't talk to the car, so we couldn't pull any info. Going to a BMW indy shop, next

You probably got intermittent elec shortage somewhere in the engine bay & underneath the car. A nice dry-out in the sun is the least you can do since you're in FL.

Let's imagine what happened when you hit the 1-foot puddle at 50MPH, First the water will gush into the grille, through radiator & fan, into engine bay. The first impact to the electric connectors would probably be CPS, VANOS solenoid and MAF, etc. I will check on every connector to see if there's any water residue. Going further back, O2 sensors, Throttle connector, DISA connector, etc.

If you let me guess, I'd say MAF, but that's just shooting from my hip. :D

Good luck!

only 1 code was found: p1835. Having trouble finding a BMW-specific definition

Thanks! Yeah, I had a similar train of thought. Not sure if you read the first post, but I spent a day disconnecting every electrical connector in the engine bay and spraying connecter cleaner through both sides of them. Next step I think, is to pull the tcm and clean both sides, of the harness/connecter.

Did you also clean and dried the electrical connector at the trans?

The generic description for your code is: -

P1835 - Transmission Transfer Case Differential Lock-Up Solenoid Short Circuit To Ground

Assuming you have an LCI model, I'd suggest you look at the actuator motor and wiring on the transfer case.

*edit* - just read some of your earlier posts and it seems you have an 02 4.4i? In that case, no transfer case actuator motor...

So, back to upallnight's suggestion of the electrical connector on the transmission. Others have had intermittent trans fail safe issues when driving in the rain and traced the issue to this connector.

:iagree:

more info. on P1835 code
 

I found a site that lists the Pxxxx codes for BMW...

P1835 Pressure Control Solenoid 'E' Circuit High

This would indicate what has already been suggested is correct - the circuit to the trans. mechatronic is faulty (or the mechatronic itself is faulty), with an open circuit connection (is that an oxymoron!? :confused:) to the E circuit pressure control solenoid.

Time to give that connector a jolly good clean! :stickpoke

The connector in question is called X8505 and it's location varies a little, depending on which transmission you have...

http://i49.photobucket.com/albums/f2...psfl3bzjy3.png http://i49.photobucket.com/albums/f2...psz5ufbbbp.png

Interestingly. the problem has self-resolved. This connector however, will be the first place I look, if the problem should return

If the abs mod. Is gone out it can cause trans falesafe mode. Next time it does it, unplug the abs and drive it. If it goes away have your abs mod. Rebuilt.

I had nearly the same issues after a deep water experience. Heavy rains left 10 inches of water in my commute path. Even though I went through it slowly, every error message possible appeared on the dash when I shut the vehicle off. All of the fail-safe messages came through. The dealer determined the engine harness shorted out. Fortunately, my comprehensive insurance covered the $1837 bill as storm damage. The technician did tell me though that all of the harness connectors seemed "dry", missing any silicone grease to aid in sealing them. About a year later, I got the transmission fail-safe warning after going through a car wash with an undercarriage spray. It dried out the next day and went away. A few weeks later another heavy rainstorm triggered a full shutdown of the transmission to the point I couldn't get it out of neutral. After letting it dry out for two days, I was able to get it to move and got it to the dealer. The harness connector to the transmission was absolutely full of dirt and moisture and no seal left. They cleaned out the sockets and polished the pins and I haven't had any problems for more than 100,000 miles.

2002 X5 3.0 305,200 miles
2014 428i 19,500 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird Under restoration