Engine Failsafe + Trans failsafe issues

[zettabomb]

Have been having a weird issue with my new '98 740i. I left it sitting for about 5 weeks, shortly after purchasing. Come back to the transmission and engine acting up - "Trans. Failsafe Prog" which leads to limp mode and only 3rd gear, and "Engine Failsafe Prog" which leads to a stall. It will do both of these whether moving or not. I've heard this can be either low voltage or sometimes ABS, so here's a list of things I've tried, in chronological order:



Recharged battery. Still stalls sitting in driveway.
Replaced alternator + radiator + belt. Alternator tested around 30A (should be 120A) and had coolant in it. I knew there was a leak in the radiator, so I replaced both along with the main belt since I was already there. After this it ran for around 40 miles without an issue.
Unplugged ABS module even though it wasn't giving the "trifecta" lights in the center.
Reset the ECU (I think) with Test No. 21 in the instrument cluster. Ran for 1.7 miles without an issue (longer than in typically would) but still stalled sitting in my driveway after I got home.


I've read codes with INPA plus a regular OBDII reader. INPA gives me an error in the transmission "129 CAN-TIME-OUT DME". The OBDII reader gives P0505, which is I believe idle air control - the idle *does* seem weird, it'll go back and forth every minute or so between what sounds "good" and a slightly rough idle at lower RPMs.

An interesting thing to note is that over those 5 weeks, the rear right window regular was broken and the window kept slipping down. I had a friend check on it and push it up but some water definitely got in because there was a new book (my Bentley manual!) sitting there and it's got wrinkled pages now. I've considered looking for water damage there, though it could be a lot to take apart. I believe the battery cables may be on that side though since they run from the trunk.

Where should I start looking for diagnosis? I'm somewhat opposed to the dealership, and I've got plenty of tools, time, knowledge, and willingness to learn. I've got the regular K+DCAN USB cable, and a P.A. soft cable.

NINJA EDIT: It's a new battery, tests at around 890CCA. The car has DINAN engine and transmission software.

[Mayorchuck]

When you say you reset the ECU (DME), do you mean you unplugged the connection and found no moisture? If you had a coolant leak in the engine bay, I would pull the connections off the DME and TCM and make sure they are dry. The sit next to each other in the ebox.

If water found it's way under the passenger seat, you need to address that if it's you issue or not. There is a main fuse block and several splices there.

http://i845.photobucket.com/albums/ab16/Mayorchuck/E38/May2014036.jpg (http://s845.photobucket.com/user/Mayorchuck/media/E38/May2014036.jpg.html)

Under passenger seat:

http://i845.photobucket.com/albums/ab16/Mayorchuck/E38/May2014234.jpg (http://s845.photobucket.com/user/Mayorchuck/media/E38/May2014234.jpg.html)

http://i845.photobucket.com/albums/ab16/Mayorchuck/E38/passseatfuses.jpg (http://s845.photobucket.com/user/Mayorchuck/media/E38/passseatfuses.jpg.html)

[zettabomb]

When you say you reset the ECU (DME), do you mean you unplugged the connection and found no moisture? If you had a coolant leak in the engine bay, I would pull the connections off the DME and TCM and make sure they are dry. The sit next to each other in the ebox.

Sorry this was through the instrument cluster. I'm not sure what it resets, but test no. 21 says "reset" and a friend told me to do that.


If water found it's way under the passenger seat, you need to address that if it's you issue or not. There is a main fuse block and several splices there.

There's definitely a good chance there was water there, I checked today and I can see a small "coffee stain" on the carpet right next to the rear right door kick plate. When you say "under the seat", do you mean literally underneath, as in, remove the seat to check?

[Mayorchuck]

Yes, it's under the seat. As you can see here, it sits in the lowest part of the pan that is just perfect for holding water. This is often a victim of clogged sunroof drains as the water comes down the A pillar. The first photo above is the DME in the ebox. You will want to remove the entire top of the ebox, located in the engine bay on passenger side firewall, and just unplug the big modules. The connectors are on top so easy and quick to check.

http://i845.photobucket.com/albums/ab16/Mayorchuck/E38/May2014233.jpg (http://s845.photobucket.com/user/Mayorchuck/media/E38/May2014233.jpg.html)

[zettabomb]

Yes, it's under the seat. As you can see here, it sits in the lowest part of the pan that is just perfect for holding water. This is often a victim of clogged sunroof drains as the water comes down the A pillar. The first photo above is the DME in the ebox. You will want to remove the entire top of the ebox, located in the engine bay on passenger side firewall, and just unplug the big modules. The connectors are on top so easy and quick to check.

Pulled all three modules from the ebox and their contacts are incredibly clean, as are those for relays, fuses, other things inside. No dice.

I'm going to pull out the seat tomorrow I think. What really did it for me was that when I got into the car today, my glasses fogged up immediately. It's mid 70s outside but no rain for a few days - and yet very humid inside the car? Sounds like it's time for a very expensive game of Where's Waldo (Water).

[zettabomb]

Here's what's under the seat:
604075
Not honestly too bad. I'll clean them tomorrow and see if it helps.

I also checked as many different modules as I could with INPA and noticed a few things. First, the coolant temp (as reported by the IKE) sometimes is sporadic and reports an invalid value. Second, the DME doesn't seem to throw an error even when it goes into failsafe mode. And third, the IKE gives a "coding incomplete" and "clamp R" error, neither of which I really understand. However, could an error with the IKE cause the engine and transmission to die?

[zettabomb]

So, an unfortunate update.

Last year I'd replaced the DME and EWS at a local indie (who even had a DINAN guy to reflash the tune) and everything seemed fine. Ran perfectly well through November or so, when I stored the car for the winter. Came back out a few days ago to start it, nothing lights up, gotta be a dead battery right? Charged the battery overnight, plug it in, everything is great, starts right up. Next day, just to be sure I started it again (still on blocks - too much stuff in the way right now to move it) and guess what, engine + trans failsafe, coolant temp pegged at max, engine stalls, won't even try to restart.

This time, I tried unplugging the coolant temp sensor to see if there was any corrosion there but it was very clean. Look at the codes gives a similar readout from before, this time using BMW Scanner 1.4 the EGS shows "CAN Timeout DME". The indie had said this last time, that the DME was hitching and thus allowing the engine to stall - and that required replacement. Somehow I doubt it failed again so soon, but I suppose it's possible. As before, connections in the ebox are very clean. I have noticed some wire harnesses are a bit cracked, but the wires underneath look fine.

Any suggestions?

[georgebest]

Bad battery?

[zettabomb]

Bad battery?

I'm thinking this might be the case. It tested fine last year but who knows, maybe it's bad after the winter. It's got a 3 year warranty so I''m going to take it in and see if they'll replace it. My smart battery charger gives it less than 500 crank amps *warm* - but who knows if that'll be enough to convince the parts guys.

[zettabomb]

Battery is somewhat weaker than last year according to the parts store's battery tester (probably should've used a battery minder) but not to an extent that it should've been an issue. Just to be sure, I got a second large and known good battery (also around 900CCA available) and connected it to the jump leads under the hood. While running, voltage didn't dip below 13.6V when measured in the ebox. I also pulled the DME apart to check if there could've been water damage over the winter but there wasn't a spot of corrosion anywhere.

I did try unplugging the coolant temp sensor as well. This still gives the same issue. Additionally, the DME throws an error because it's unable to read the coolant temp, which it doesn't normally do when it stalls out. My theory right is that it's a bad ground, somewhere. Since one end of the temp sensor is grounded, that could cause it to read bad. It's also that the DME is bad again but I still doubt that.