e46 automatic transmission query

[decsnz 0]

I have brought a 98 E46 318i. It automatically changes down gears when I apply the brakes while descending down a hill. It can be quite abrupt and give a real jolt at times. Is this normal?

Cheers

[hybrid 1039]

I have brought a 98 E46 318i. It automatically changes down gears when I apply the brakes while descending down a hill. It can be quite abrupt and give a real jolt at times. Is this normal?

Cheers

Sounds like you have the same issue im trying to fix ... My gearbox was rebuilt.

no its not normal .. im in the middle of trying to diagnose it myself as everyone in auckland (including the so called experts) have all had a go and come up with nothing.

I have traced it down to a problem with the EGS (gearbox computer) and the way the adaptive transmission handles the timing of the changes ...

you can temporily fix it but reseting the EGS learning maps .. but it comes back after time

get in contact with me over PM as im looking for other people with the problem to compare software versions of the auto box with.

atleast I can use the data I gather to go to BMW and get them to bloody do something about patching the software!

[hybrid 1039]

here are some details from another post I made.

I went over to a Warlocks place to try out his software he just bought ... So I didnt waste any time getting info about my problem

for a bit of back info on my delimar... (sorry its a post I dragged from e46 fanatics) 2nd gear thumps on down change from third on odd occasions.

Sorry to drag this post up again .. but I thought Id shead some light on what I personally think the problem is.

Just for the record: I had the ECU and gearbox GCU reflashed to "latest versions"

The problem only seems to happen when im driving around town ... however if I go for a long drive or go on one of clubs runs and I hammer it its fine. Its stays this way for about a month.

This draws me to the conclusion that its a fault in one of the 'learning maps' of the gearbox control computer. It seems some of you who have had the updates done may just have that "majical" update that has the problem beat. Whats more annouying is there is nothing officail in the BMW TIS about this. Somebody somewhere knows about this problem and has the majic "keys" to it ...

I guess what we need to do is try and write down a register of software revisions.

Another thought is we can always try what the ex-ja p e36 with "jatco" autoboxes have to do .. and perform a GCU reset. Does anyone have any info on how to do this on a e46?

peas.

As you can see the EGS is the module that controls the auto gearbox.

One thing we did do is reset the EGS learning maps .. and what do you know .. I have nil gearbox problems. Only thing is this will only last until my EGS decides to change to the new map.

In the realtime data output from the EGS it did show that I was now useing gearbox control pattern "a" .. which also is of great interest to me ... next time it happens I will record the gearbox pattern and post it here.

the hunt continues.. but at least I now can confirm my suspicions. Im now looking at ways to stop the learn function or to "ban" the offending gearbox map from being loaded by copying the owrking maps over the top of the offending map.

[*Glenn* 854]

I have fixed 3 cars in the last 2 weeks with the same problem. Ring me about both of your cars. I may be able to help

[hybrid 1039]

Will ring you first thing monday glenn

there about 1000213012938 people in the states who would like to know the resolve for this too

[hybrid 1039]

thanks for the phone call glenn..

The diagnosis starts. Its seems from glenns experience around this type of issue share by it seems Audi's and Merc's who have similar bosch/seimens control systems that it infact maybe something to do with other sensors non related to the gear box.

glenns words:

The gearbox learning functions not only have adaptive behalvior for your style of driving but also adapt for faults other sensors around the car may be sending.

We are going to be diagnosing this next week and hopefully come up with some awnsers.

Will keep everyone posted around this as it will no doubt become more and more of an issue for e46's and other cars as more and more people buy these types of vehicles.

[wild_weston 0]

thanks for the phone call glenn..

The diagnosis starts. Its seems from glenns experience around this type of issue share by it seems Audi's and Merc's who have similar bosch/seimens control systems that it infact maybe something to do with other sensors non related to the gear box.

glenns words:

The gearbox learning functions not only have adaptive behalvior for your style of driving but also adapt for faults other sensors around the car may be sending.

We are going to be diagnosing this next week and hopefully come up with some awnsers.

Will keep everyone posted around this as it will no doubt become more and more of an issue for e46's and other cars as more and more people buy these types of vehicles.

Interesting. Mine does the same thing (shift down when braking on a hill). Guessed that that was the way the gearbox CPU was programmed to work. Doesn't really bother me but it would be nice not have it do it.

Post an update when you have one on this. Could well be a sensor somewhere else that has gone funny.

One thing I've really noticed since owning a E46 is that it tells you bugger all when sesnors fail. In comparison the e36 told you far too much (saying things had gone when they hadn't).

I reckon the E46s need another warning light out on the dash ("sensor failed" light). BMW probably thought about this and decided not to - as it would be permanently lit!

Might be a bit of a long shot but I posted a way I read about clearing the jacto gearbox in an e36. Didn't work for mine at the time. I got it off bimmerforums and it didn't state it was for the E36. Might try and give it a go in the E46 and see if that helps.

Original solution:

Turn you ignition key to setting 2 (instrument lights come on but car isn't started).

Depress the accelerator all the way to the floor for 25 to 30 secs.

At this point you should hear a slight noise, this is the automatic transmission cpu resetting.

Then start the car (obviously take your foot off the gas first).

Apparantly the car learns your driving style over the next thousand Ks and sets itself to that.

Edited May 11, 2008 by wild_weston

[westy 614]

My E46 has a clutch

[hybrid 1039]

Westy shut your hole

Think we may have found a mass air flow sensor to try ...

[westy 614]

Hehe, Im feeling quitely relieved.

Sounds like you guys are having all sorts of trouble with it.

Best of luck finding a solution.

[hybrid 1039]

Interesting. Mine does the same thing (shift down when braking on a hill). Guessed that that was the way the gearbox CPU was programmed to work. Doesn't really bother me but it would be nice not have it do it.

The down change when going down a hill is normal.... its the 3rd into 2nd .5 sec delay -> disengage -> re-engage violent thump thats isn't .. you don't sound like you have this issue.

Mine also when coming up to a full stop at md pace when its really playing up thumps into first then off into neutral hold. Keep in mind my gearbox is fully rebuilt with OEM parts / fluids only a year ago.

Might be a bit of a long shot but I posted a way I read about clearing the jacto gearbox in an e36. Didn't work for mine at the time. I got it off bimmerforums and it didn't state it was for the E36. Might try and give it a go in the E46 and see if that helps.

Original solution:

Turn you ignition key to setting 2 (instrument lights come on but car isn't started).

Depress the accelerator all the way to the floor for 25 to 30 secs.

At this point you should hear a slight noise, this is the automatic transmission cpu resetting.

Then start the car (obviously take your foot off the gas first).

Apparantly the car learns your driving style over the next thousand Ks and sets itself to that.

Nah that doesnt work. The only way I know of to reset the DME and EGS learning maps is to plug a diagnostic computer into the ODBII port and reset them. It only works for a small amount of time anyways .. it isn't the root cause of the problem.

Glenn has some pretty strong ideas of what it is .. which make a lot of sense and most people would of never have thought of .. and glenn said its just because he deals with these sorts of problems every day and has learnt the way ODBII Bosch / Semens systems work.

I'm hopefully borrowing a mass air flow sensor off somebody see if its infact that.

Will keep you posted on what glenn finds.

[decsnz 0]

Mine does the 3rd into 2nd thing, but not the disengage, though it is a pretty good thump. Always the same place on the same hills.

[hybrid 1039]

yeah same with mine. the dis-engage is if you look the engine revs drop to about 1000 RPM (depends what you reveing at obviously) then jumps back to 2nd causing the thump as the engine is being asked to spin back to say 2500rpm from 1000.

[m325i 705]

My old man's e46 has had a rebuild. I went in it this morning and the nbox is kinda 'thumpy'

I'm sure that didn't help anyone.

[hybrid 1039]

yeah is no doubt is something similar to what us lot are delaing with.

Im actually trying to work out why even after the gearbox was built with OEM revised version parts .. It starting doing this...

one things for sure.. Cars are just getting overly complicated .. blame the greenies

[decsnz 0]

Hi Hybrid, Is there a way of getting a live comms dump while the car is moving? What is your thinking behind it being the air mass sensor?

[elmarco 56]

one things for sure.. Cars are just getting overly complicated .. blame the greenies

Or the lawyers!

Mine actually has a thump when you take it out of park if it has crept a little on the handbrake. Don't think it would be related to your issues though.

[keen 6]

My wife has a 2000 e46 ex Japan 318 her car does the clunking bit too but it is intermittent and a "star" comes up beside the indicator on the dash when its playing up. I would like to take it to Botany motor works but its a little to far away for me. is there a resolution to this yet?

[*Glenn* 854]

My wife has a 2000 e46 ex Japan 318 her car does the clunking bit too but it is intermittent and a "star" comes up beside the indicator on the dash when its playing up. I would like to take it to Botany motor works but its a little to far away for me. is there a resolution to this yet?

You would need to get your wifes car scanned...there is obviously a fault...either engine or gearbox related

[hybrid 1039]

Hi Hybrid, Is there a way of getting a live comms dump while the car is moving? What is your thinking behind it being the air mass sensor?

Thoughts are glenns not mine .. hes saying that he has had experiences with the bosch electronics .. and he had replaced a MAF in an audi the week prior with pretty much the same issues Im having. The gearbox trims counter for problems too .. and with incorrect data coming from the sensors .. the gearbox doesnt know weather its aurther or marther.

I have used some other software and check for error codes... nothing found even though the problem remains.

Having a really hard time tracking down a MAF for a 330©i so cannot start testing until I get one of these.

Brendon and I did capture a load of real time data from the EGS. You can really track/graph everything .. however As glenn said unless we do a before and after comparison with known good components, there is no point even starting.

One thing I do know is since I have been whinging about this .. more and more people have come to me with similar problems with their gear boxes ... everything from e39's to x5's and everything in between.

Seems a common problem.

In other news .. While I was racing it this weekend ... it gave me a chance to really give it stick ... the fault started to happen once things got quite hot .. then stopped again when things cooled down a bit. I had only one compression lock up down the back straight but I managed to catch it with a manual down shift and a bit of matching the revs to the drive train speed so no major