Transmission overheat p1793

Gixman05 · #1 12-23-2019, 10:41 PM

After the car had been sitting for a few days the car fridge drained the starter battery dead. Jumped started it and now has come up with transmission overheat p1793 and has locked it in 3rd(trans fail safe prog). This is the second time in 2weeks that I've had to jump start it for the same reason but never had this happen with previous jump starts. Is it just coincidence or have i fried etc. My autel scanner said something like etc module and inpa said p1793 over temperature. It has recently done some heavy towing long distance. Did it with ease and hasn't had any issues till now.

wpoll · #2 12-24-2019, 12:38 AM

Jump starting a car doesn't mean it will run correctly - it still has a flat battery, even after you jump it. All bets are off until it's fully charged - and running the car stationary for a few minutes won't do that.

Worry about this if it is still an issue once you have replaced the battery or at least fully charged it with a charger. A flat battery can cause all manner of gremlins, esp. transmission issues.

Gixman05 · #3 12-24-2019, 12:50 AM

Hey wpoll i think she's done her dash this time the ole mole, the battery is fully charged and its still faulting. Dropped the oil out to check it and its full of pretty little sparkly bits haha so I'll drop the pan off shortly and check whats hiding inside. Anyone need spare parts. No wonder the i couldnt clear the fault code...

andrewwynn · #4 12-24-2019, 12:52 AM

BMW's do not like low voltage. If you scan for codes you'll usually get more than a dozen any time you have a drop below 12. Zap the codes keep your battery above 12v. If you run an always on accessory, hook up the car to a battery tender when you leave it overnight

Gixman05 · #5 12-24-2019, 12:56 AM

Thx andrew yeah i run dual batteries now as ive noticed how much dramas you can have after a dead battery. Doesnt really matter now though unfortunately it'll be getting scrapped if the trany is toasted

Gixman05 · #6 12-24-2019, 03:09 AM

false alarm Looks like sand had fallen into the oil drain container when i pulled off the bung. Dropped The pan and its as clean as can be as is the filter. Possibly sensor issue or ect fried. Anymore thoughts or ideas for this one. Can you test the modules with inpa.

Clavurion · #7 12-24-2019, 03:25 AM

You can check if the transmission oil temp sensor is showing logical figures in EGS module.

EODguy · #8 12-24-2019, 03:59 AM

Transmission cooler block is most often overlooked and if you've had coolant disappear in small amounts even with expansion tank replacement those little o-rings should be replaced. Leaking o-rings can also allow spike in transmission temps.

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andrewwynn · #9 12-24-2019, 12:52 PM

I've has a few times I had transmission limp mode from non transmission problem. I definitely would start with assuming it's not the actual transmission.

First time was wonky voltage from the alternator because the moron that installed it only tightened the B+ finger tight. (that moron was me)

The order times was from water getting into the main transmission connector on the back of the transmission.

wpoll · #10 12-24-2019, 01:58 PM

Quote:

Originally Posted by andrewwynn

...

The order times was from water getting into the main transmission connector on the back of the transmission.

Not a lot of rain in Queensland right now...

Also, our diesels have a large plastic under shield that covers the entire transmission and transfer case, making it pretty unlikely that water can get up there. Never say never though...

It sounds rather odd that the error pops right back when cleared, without a run. Perhaps it's not clearing correctly? What scanner are you using again?

Are there any other symptoms beyond just this error code? It trans still in limp mode?