Auto Trans ECU Question

[crystalclear]

mine is dead - replacing soon

scenario (had a previous thread): faulty maf, rear o2's, evap leak - all caused by getting stuck in the water/mud for 6-7 hours

1) bad maf = limp mode (car seemed to run only in 3rd)
2) changed out maf = and drove 1mile home in "D", which i am guessing was just locked in 4th with no shifting up through the gears

this was all done with a trans ecu that went bad at the same time the maf did (took water into the cabin)

i asked a couple people already, but wanted a little clarification:

- i won't be driving the truck again until replacing the ecu, but for my learnings sake, what is the danger to the car/me if i were to drive it?
- once the new ecu is in - should i expect regular trans operation to return given nothing else is faulty?

 

[KyleT]

did you flush the transmission? mine was in for less than 30 mins and it needed a new transmission. i towed it home and ran it for 30 seconds to get it on the lift before draining and refilling 3 times.

it will only be in 3rd gear till the tcm is replaced.

 

[crystalclear]

did you flush the transmission? mine was in for less than 30 mins and it needed a new transmission. i towed it home and ran it for 30 seconds to get it on the lift before draining and refilling 3 times.

it will only be in 3rd gear till the tcm is replaced.

sent you a pm - thanks for the info

haven't flushed yet - as i have been advised by more than a couple, to leave the fluid alone for now

you/anyone have insight into where/how water could enter the trans? obviously it may be dependent on the depth of water

car is sitting for now, so no further damage should arise

 

[KyleT]

dont flush, i mean, do drain and refills. sent you a pm back.

 

[crystalclear]

thanks kyle, just asked the same question via pm

will be doing some drains/fills in the coming days

out of curiosity - how much water does it take to kill/almost kill a lr trans?

 

[carlosz]

the zfhp24e fitted to a disco 2 is sealed to the elements, unlike the zfhp22 of earlier models (d1 up to 98 or rangie up to 95) where they had a the throtle kickdown, this kick down would break and cause fluid leakeage and ingress of elements.
so technically speaking unless you had existing seal damage is is nearly impossible for standing water to enter the zfhp24e trans.
your electrical connectors on the other hand may be soaked and shorting out thus causing your issue.
the ecus on the d2 are located behind the glove box so yo will need a fair amount of water to have entered the cab and more than the trans ecu would be affectected.
double check the electrical plug leading to the trans, disconect and spray clean with electrical connector cleaner, dab some diaelectric grease and recconnect, reset codes and run.
it may just be a wet glitch/gremlin.
if you are curius, do drain and refill the trans, use a clean pan do drain so you can id water in atf mix.... if water in it atf will be milky/ strawberry milkshake colored.
I would be concerned about water in diffs thou.

 

[R_Lefebvre]

so technically speaking unless you had existing seal damage is is nearly impossible for standing water to enter the zfhp24e trans.

Well that's bullshit. I also suffered a wrecked trans from sitting in water. Was told the labyrinth seal on the input shaft sucks water in. I don't know if it was that for sure, but it was in there.

In my case, I was only stuck in the water for about 5 minutes. TCM got wet and stopped functioning. I removed it, and was stuck in limp home mode, locked in 3rd gear. Drove back to camp like that, opened up the TCM, sprayed it out with electrical cleaner, blew it off with compressed air, and it was fine. The trans was not, however. I changed the fluid 4-5-6 times, but it let go several months later.

It takes only a teaspoon of water to wreck the trans. The water soaks into the clutches. Then when operating and the clutches heat up, the water flash boils from inside, and blows apart the clutch linings. You MAY be able to save the trans if you rebuild it now with new clutches before it fails and takes out the steels and everything else too.

I just said fuck it all, and don't have to worry about the damn thing anymore.

 

[Mongo]

holy shit I'm agreeing with Rob!...

 

[crystalclear]

thanks for all the info guys - ill be taking care of ths today/tomorrow and will report back what i find....

 

[carlosz]

that is why I said "technically" because during normal use anything can happen,
manufactures have tested their stuff under their own controlled environment and then printed the findings or told us techs what they have, but 10yrs down the road or 10's of 1,000's of miles later only the user knows the results.
how ever, the zf22 still has the throtle kick down as a weak point over the zf24 sealed.
Im sure land rover did not submerge the test vehicle 3 ft under water with a hot drive train and expanded metals for a long time if any time at all.
so "technically"... is the key word, im not defending the vehicle or lr, im following on crystal clear's post of the possibility of water ingress and still driving home, as you stated it would be next to impossible to drive even with a tea spoon of water in it as that trans would go bad just idling.
he mentioned ecu failure, I replied the near implasibility of it as it would take a deep submertion cycle to reach ecu to cause it to fail.(probably to the top of the seats)
so if he drove home the likelyhood of a failed trans is almost null not impausible, if ecu did not get wet then it would leave open the possible shorting at the connector under the car .
he has not said if water level got up to trans ecu.
im just following diagnostics logic, as a tech i have to do it so I dont give out an incorrect diag to a customer.
imsure clear is not eager to drop lots of change on a maybe this or that hunting for an issue but rather wants to resolve his problem on an expedited and economical manner.
as profesinal tech, I will be the first to admit the pit falls of these trucks, and as an owner I have learned their pros and cons.

 

[Mongo]

Rob sunk his in water for 5 MINUTES. Klye's was swimming for 30 minutes and the OP sank his in water for 6 or 7 HOURS! He got it deep enough to get the tcm wet so he got it deep enough for water ingress into the transmission

As a professional tech, you need to learn how to read...

 

[crystalclear]

ok, i see some clarification is needed....and perhaps, it will answer/pose some new questions

1) the auto trans ecu (under driver seat) - has temp/perm failed - there was about 1" of water only on the drivers side - but only about 1/4-1/3 up the carpet (towards center console) - so techincally not "much"
2) the way i got stuck was kind of unique - passenger side was plenty out of water - bone dry --- and i was centered on the peak of the rut - so much so, that my tires were off the ground (under the water)
3) because of this - despite it sounding a tad impossible - there is a chance my trans (and the seals in question) were never actually under the water line and never had a opportunity to suck in water as they cooled
4) drove home in limp (3rd) - after replacing maf - drove another mile in what had to be 4th?
5) mode switch doesnt work - which i am guessing is tied to the auto trans ecu
6) would the tcu failure cause any of the other modules to fail despite others remaining dry?
7) both rear o2's are showing up - i am guessing it is due to fouled connections, wd40 ok? (refer below)

hope that helps, maybe not....

also - in a pinch, is wd40 "ok" to attempt in cleaning out the tcu and other connection points?

 

[KyleT]

Like i said wd40 saved some of my ecm.s.
Maybe there was a better alternative but at the time it is want i had.

 

[crystalclear]

tried to upload a pic of the truck in water, but not working....

if you guys could see it, you would probably 1) laugh that i didnt make it 2) suggest i am overreacting

but in the end - got stuck, and just deep enough to let a trickle into the driver side...

 

[carlosz]

crystal, did your battery run down during the time you were in water?, if so that may be the reason for trans ecu responding the way it did. default mode is limp, which extends the shift points and starts in 3rd to keep trans from frying.
if you have a scanner a reset may do, if not do a hard reset by disconecting the batt for 5 min. if you have or will be replacing the 02's then a adaptation reset is in order.
more or less sounds like your connectors became wet, then sent wrong signals to ecu's and thus a whole lot of codes were set, enought to send the thing into limp mode.
you may be surprised as to how resilient those ecus can be.

 

[KyleT]

I've seen spilled big gulps take out a tcm....

 

[Mongo]

Since when does disconnecting a battery reset any of the computers on a D2?
So changing the MAF didn't help, correct? Clean the tcm, I've seen them cause all kinds of issues, but be sure to drain/flush the transmission and let us know what the fluid looks like.

 

[carlosz]

I've seen spilled big gulps take out a tcm....

true, possible caused by the syrup I dont know.
back in 02, my cousin had just received the title for his 96 p38... happy he had paid it off and it was owned out right he decided to off road it.
his brother in law was shotgunning... long story short they became high centered in muddy water up to the door moulding... passenger asks what they'll do now, driver responds with sarcasm get out & push, dummy opens pass door and fills floor board with enough muddy water to cover becm.
it happened soo quick the driver barely said "close door".
that thing went into fritz... all lights on and flashing, wipers on, washer squirt, alarm sounding, no remote response.
battery was disconected in what seemed hours, but in reality 5 minutes max, truck sat in water for another hour before being pulled out.
the following day we pulled carpet, seats and becm, opened becm and cleaned every board with fresh water, let it dry put together and the only damge it received was the fuel door release signal stopped working.
to this day he still drives the darn thing with same fuel door issue.
in retro spect one of my classics broke an axle crossing a creek with water up to head lights, this caused the engine to hydrolock so it sat in creek water for a good 1/2 a day
my engine ecu has never ran right since.
so "you will be surprised how resilient they can be"

 

[ptschram]

I've seen spilled big gulps take out a tcm....

Driving them into big puddles does the same

 

[R_Lefebvre]

Rob sunk his in water for 5 MINUTES. Klye's was swimming for 30 minutes and the OP sank his in water for 6 or 7 HOURS! He got it deep enough to get the tcm wet so he got it deep enough for water ingress into the transmission

Just to make things a little clearer, here's my situation:

I was in the water just long enough to jump out the window, pull the strap off the hood, hook it up to the rear, and get the guy behind me to yank me out. The water never even equalized in the cabin, but it did cover the TCM and the amp. The speakers started making all kinds of bad noises until I unplugged it. And I unplugged the TCM.

I cleaned the TCM and it was fine.

I've been through deep water many times. The problem appears to only happen if you stop moving.

Here is what the fluid looked like after the transmission failed. This is a few 1000 km after it had been flushed thoroughly (5 gallon pale of ATF). That's clutch material clouding it, not water. I had just started to think it was going to be ok, when I was left stranded.

Inside the filter.

I hoped the trans losing drive was due to a clogged filter. So I changed the filter and ran another 20L through it. No dice. The trans worked, but it didn't feel good and I knew it was just a matter of time. Not wanting to be left stranded again, I solved the problem once and for all.

manufactures have tested their stuff under their own controlled environment and then printed the findings or told us techs what they have, but 10yrs down the road or 10's of 1,000's of miles later only the user knows the results.

Yes. I was an OEM engineer, we used to say "9 women can't make a baby in 1 month". You can only accelerate testing so much. There is no way to really test a system with 10-20 years of use within a 4 year product development cycle.

That being said, the factory only tests to 24" of water anyway.

How/why does Crystal think the MAF was bad? Never heard of a MAF causing limp mode. You can (and I have) driven with the MAF completely unplugged. You almost wouldn't know it.

I would expect, if no water got in the trans,and you replace the TCM, everything else will be fine. The trans connector is a really good design. But check it. Mine was factory-clean inside after all it had been through.

even with a tea spoon of water in it as that trans would go bad just idling.

Not true. I drove all the way home before I could flush it. Ran fine. Didn't even know anything was wrong. After flushing, it still went 1000's of miles before failing.

Like i said wd40 saved some of my ecm.s.
Maybe there was a better alternative but at the time it is want i had.

I now carry the electrical contact cleaner full-time. It's way better. Brake cleaner works too. That's what I used on the amp. Amp still works to this day.

Since when does disconnecting a battery reset any of the computers on a D2?

Sure doesn't! I left my battery disconnected for a month, and when I plugged it back in, my 4 Amigos were still partying!

so "you will be surprised how resilient they can be"

It's all in the timing. Power must be removed from the device IMMEDIATELY. Then, it must be cleaned ASAP. Fresh water can work in a pinch, but it MUST be blown out thoroughly with compressed air before you hook it up again.

I actually left mine sit on my black hood in the sun for an hour to dry out before I got back to camp. Maybe that helped.