transmission woes

[bstizzle 1]

my 2000 318i e46 was running rough at idle plus had some acceleration lag. Reading forums led me to look at maf sensor, and also using higher octane fuel.
I put some 95oct in and straight away it ran much better.I also took out the maf sensor and gave it a clean.
Almost straight away when I drove car, the trans warning cog light came up and gear changes are very hard. Especially when am braking and the trans down-shifts.
It seems to slam from 3rd to 2nd gear almost as if its changing while revs are too high still.
I have the following codes come up- 7d&a9, which relate to the pre cat o2 sensor, and 78&79 which relate to maf sensor (now I was curious after this problem occured so I took car for a spin with the maf sensor unplugged and it seemed to make no difference to either engine performance nor the trans issue)
The other code I getting(which seems more relevant to trans issue )is code92- CAN torque interface. I also had code 32- gear monitoring 1 but this came up in a scan done a week or so prior to the issues I now having.
Thinking that it happened straight after I took out maf , I thought I maybe knocked another plug loose or something or that I made something glitch in a computer.
I read that the codes possibly relate to the trans being unaware what revs/torque output the engine is doing.
I have checked all fuses, and now want to look into any wiring/connector plugs that link trans to engine/ecu. Any help on where to look would be awesome.Or any thoughts at all on how to resolve this.If it is just a glitch type thing do I need to do a hard reset(disconnect battery??) as you might do when a laptop crashes?
I oringinally thought it seemed like a low trans oil problem but , a)- the fact it happened in conjunction with me messing about under the hood, & -the car only done 170k kms with (supposed) lifetime trans oil, and no sign of leaks etc I very much doubt thi is the case..
Any ideas people??

[BM WORLD 1283]

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[*Glenn* 854]

If you would like a proper diagnosis of your problem Bernie, give me a call. You are floundering with misinformation and a substandard scanner

[bstizzle 1]

thanks Glen I may do, tho I dont think buying a new trans is on the cards just yet i want to find what really is wrong. The scanner is a mates who does a lot of diagnostic/repair work on european cars.
I'll post the pics of scan results,

well, I trying to post pics. my f##kn internet is sh*t at mo

Edited January 8, 2016 by bstizzle

[zero 1162]

Glenn is right, but as a sidenote, what did you clean the maf with, and did you physically touch the maf with anything?

Also, have you been driving the car on 91 unleaded?

Our cars should be run on 98 only.

[bstizzle 1]

hey Nathan, yea I did touch maf. paper towel wrapped around small screwdriver. prob a sh*t idea in hindsight.

I have only owned car a few weeks so have been unsure of fuel. I called prior owner- he said 91 fine but i think he a muppet. after researching I did find that 91 isnt ok so have been putting high as poss in (95 usually. who does 98?Gull?)

I think Ill get a new maf and see how goes.

I just tested battery and it reads 12.06volts. ok? or too low?

[zero 1162]

You have probably damaged the maf - you should ONLY use maf cleaner, and no physical contact from rags or paper towel.

Before you change it though, take it to glenn to get the codes read and diagnosed correctly, otherwise you are throwing money at guesses.

Always use 98 - Gull has it, so does some BPs, Mobils etc.

[gjm 3258]

I'd suggest 12.06 is a bit low - probably should be 13.2V. Not enough to cause the problems you're having, though.

Our 320d went to ~200000 miles, likely with no ATF change. We didn't have any real issues with it, but I'd certainly never suggest that's a good idea. Change the ATF every 100000km.

Go and see Glenn (assuming he's local).

[zero 1162]

Voltage measurement will be different depending on if the motor is running or not, and how long since the motor was last run.

[bstizzle 1]

some good points there guys. thanks heaps. I poss will look into taking car to Glenn. Pretty positive I have dameged the maf now for sure. It makes sense.

[bstizzle 1]

yea, Nathan I checked while not running. I might check again now as I just went on a beer run so it may be different now

[bstizzle 1]

yea, 12.15 now. not original batt either by the looks. and poss not totally the right specs but at least am wary of it now..

[zero 1162]

some good points there guys. thanks heaps. I poss will look into taking car to Glenn. Pretty positive I have dameged the maf now for sure. It makes sense.

Damaged maf will not cause transmission faults.

Taking it to glenn will save you alot of money.

[bstizzle 1]

yea, Nathan I wouldnt have thought so. It's just the fact once I had fckd about with the maf, the test drive straight afterwards was when I got whe trans light and issues. Thats why I figure the relationship to the events. OR its a huge coincidence ..

The trans upshifts fine. both in auto and driving in manual mode. its just downshifting harsh from 3rd into 2nd when braking.

it pulls pretty hard I very surprised really. compared to the flat spot/lag it originally had. I put that down to the higher octane gas I now using. Kinda hard to believe its only a 1.8ltr. As I said tho I quite new to the world of BMW. Inpressed and frustrated all at once.

I do agree tho that I should get proper diagnosis and I intend to do so..

[zero 1162]

1.9 litre.

The extra 100cc's makes all the difference.

[*Glenn* 854]

Damaged maf will not cause transmission faults.

Yes it will the EGS get's it's load signal from the MAF sensor

[zero 1162]

Yes it will the EGS get's it's load signal from the MAF sensor

I stand corrected.

[bstizzle 1]

so, now I need to buy a new maf. who to call for this?

[zero 1162]

so, now I need to buy a new maf. who to call for this?

Go to Glenn first to make sure this is the problem, otherwise you are throwing money at guesswork.

Seriously, it will save you alot of money.

[*Glenn* 854]

so, now I need to buy a new maf. who to call for this?

Don't buy or do anything until it has been diagnosed correctly... 90% of a repair is diagnosing the actual fault first

[Andre3000 55]

^what he said. I'd be pretty confident in saying that you have f**ked your maf by shoving a screwdriver into it. If you think that is a good idea I'd be handing ALL future automotive work to a professional...

Always use at least 95 octane, 98 from mobil, caltex or bp if you like your car to run properly.

[hotwire 352]

This really is another one of THOSE threads, I absolutely concur with Glenn.

You are guessing, & probably inducing faults, & costs, as you try to diagnose.

These vehicles, any modern for that matter, need diagnosing by people that have a knowledge of what they are doing.

I have, over the years seen plenty of vehicles that have had MAF sensors replaced on a fault code, only for them to end up at work, still with the code, to find a vacuum problem causing the issue.

Cases in point:

My E39 - ABS showed RH/R wheel sensor fault. I suspected it a false code & upon checking, confirmed the module with an intermittent dead output to the sensor.

Last week, a rough idle/misfire. Scanned - 3 codes - ign cyl 2 & 5 faults & fuel trim.

Yea right I thought. Diagnosed to a split (another argh) vacuum hose. Was surprised the MAF hadn't thrown its toys too with a code

Battery voltage: 11.8 = flat, 12.8 is fully charged, mid 14v charging (varies depending on state of charge of the battery)

Certainly no disrespect but with these cars - a little bit of knowledge can be dangerous.

[Ahmedsinc 414]

Certainly no disrespect but with these cars - a little bit of knowledge can be dangerous.

^ +1

Above statement applies to everything from E34, E36 & E38 up. Have seen perfectly competent & intelligent mechanics stumped by BMWs, God help those of us that try to figure it out for ourselves!

[bstizzle 1]

well guys I have sorted it. As I thought, it was the maf. Glenn's comment about the egs getting signal from maf pretty much confirmed it for me.

Along with the error codes (which do seem to have been spot on, and do reinforce what Glenn said)

I put new maf in this morning and BOOM- trans light gone and gear shifts are great.

So thanks heaps for all the imput peeps (esp you Glenn.I will surely use your services if I do get really stuck in the future)

I am a muppet for possibly fckng the maf in the first place, but I was making sure I did the research as to diagnose myself and to only get help when and if I needed.

I dont have the cash to pay for mechanics etc, and have always done things myself. Being a boatbuider I kinda do have some sort of clue as the trade itself is really a few different trades combined..

Anyway, thanks again and happy new year fellow beemer heads..

[gjm 3258]

So thanks heaps for all the imput peeps (esp you Glenn.I will surely use your services if I do get really stuck in the future)

I am a muppet for possibly fckng the maf in the first place, but I was making sure I did the research as to diagnose myself and to only get help when and if I needed.

I dont have the cash to pay for mechanics etc, and have always done things myself. Being a boatbuider I kinda do have some sort of clue as the trade itself is really a few different trades combined..

Anyway, thanks again and happy new year fellow beemer heads..

Understood. And apologies if my PM may have seemed a little blunt... I was confident you weren't incompetent, but didn't know how far your skills might extend.

Great to hear you're sorted.