E46 transmission light

[alijanjan 3]

The transmission light on my e46 comes on intermittently and transmission goes to safe mode

Then if I turn the engine off for a minute or so, it goes away

When the light is of, transmission works perfectly, smooth an no problem at all

I know there are a lot of threads about e46 transmission and confusing too

Is it an electrical fault? How can it be mechanical where it works perfectly when light is off

Any help? What should I check first?

I'm also going to change transmission fluid anyway

The car is 2002 and it has the gm box not the zf

When I scanned it with my cheap obd cable it only had a p1031 code which I'm not sure what it is but don't think it's related

The problem is I now live rural area in Australia and it's a 300k drive to get the car to anyone to look at who may have any experience on these cars

any help is greatly appreciated

Cheers

[rowans17 19]

Best thing to do is to go get a proper code scan. Had this on my 328ci. Turned out to be a brake light switch, cheap as fix. A quick google of that code says vanos/vvti issues??? Not trans....

Edited December 6, 2013 by SN1TZR

[alijanjan 3]

thanks

forgot to mention, last few weeks the engine sometimes runs roughly for the few seconds after starting then goes to normal

dont really think the code has anything to do with the tranny but i bought an aftermarket bmw scanner hopping to get a better reading, i have to drive 300k before i can get to a mechanic who may have a proper scanner to read the ecu

while i am waiting for the new scanner, i scanned it again with the old one tonight and the P1031 code is back again (last time i had cleared it)

Edited December 6, 2013 by alijanjan

[elmarco 56]

A quick google suggests P1031 could be a cam position sensor. They can run a little rough & chew a little more gas with a cam sensor failed (as well as some power loss depending which one it is).

As to the trasmission light, no idea.

[gjm 3258]

P1031 isn't a transmission-related code... I think it has something to do with VVT, so elmarco's call on a cam position sensor could be right. Or it could be the VVT motor. Definitely fixable, if a little fiddly.

Transmission light... When you say it goes into safe mode, is it locking into a single gear? Or does it still change gear, and if so, are you getting jerky changes (when the light is on)?

Trans light can be brought on by many things, from low oil level in the 'box to duff wheel sensors, CANbus connection (the harness connecting to the gearbox) or even main battery - when was this last checked/replaced? If it is putting out low voltage, it may be sufficient to show as a fault due to low voltage on the gearbox sensors.

Sorry I can't narrow it down any more. Getting a filter and trans sump gasket kit and changing the fluid is probably a good idea (how many miles / kms has the car done?) Make sure you drain as much fluid as possible, first from the drain plug on the gearbox (remove the fill plug first), and you can get a fair amount out by disconnecting the lines from the trans oil cooler. And make sure you fill the system correctly.

[alijanjan 3]

Thanks for your reply

I think I know where the cam sensors are, will check the connections etc

The code keeps on coming back, so there must be something wrong there

As for the transmission, It shifts gear even when light is on but I think only second and third gear and its jerky, when the light is off the gear change is smooth and nice

Battery is only 6 month old and when the engine is running it measures around 13v

I have read online how even an aftermarket head unit can cause it, but the car is 100% standard nothing has changed

It has done around 180k, I am waiting for the filter kit to show up to change the fluid, have bought some dextron vi fluids too

I have read few DIYs on fluid change, anything I need to be careful about? Where do I disconnec the cooler lines? In front of the radiator?

Cheers

[Allanw 1071]

The proper scanner may help determine if there is a transmission code.

The light can come on due to some very simple things (the battery is one, the ignition switch is another) or something more complex. If it's not storing codes, it may be something like the ignition switch.

[gjm 3258]

I had my fluid changed for me because I knew it needed doing and had no time to do it myself. Use good fluid - I had planned to use Penrite AFS-FS or possibly their DX VI. The key thing is to ensure whatever you use is appropriate. If you want to drop me a PM with your email address, I have several docs I can send you.

The whole system hold 9+ litres of fluid; the gearbox hold about 4-4.5, so it is vital to drop fluid at the cooler too. You'll probably still not get all of it, but you'll get a lot more.

Here's a pic from RealOEM showing where everything is (on my car) - I anticipate yours will be similar.

It sounds as though you have a reasonable idea of what you're about. One of the important things is to fill the transmission gradually, ensuring the whole system is filled - you obviously can't drop several litres of fluid in and hope for the best! There are several threads on t'internet that help with this (I probably have some bookmarked).

Check the electrical/electronic connections to the gearbox, too.

[BM WORLD 1283]

could be low on trans fluid , does the light come on if you throw it fast around a corner??

running rough , comon issue with the m43 engine is the pcv valve is stuffed

[alijanjan 3]

It's N42 engine

Today when I went for a short drive, eml light also stayed on with transmission light.

After switchin off the engine and back on, it went away

But today transmission light kept coming on every time when I speed over 30k. I tried few times turning engine off for few seconds, every time light went away but came back on when I speed over 30k

Next time I go for a drive, I will try and see if it comes on when I go around a corner

[*Glenn* 854]

Ali... only scanning with a known quality scanner by somebody with a brain will be able to help you with this. Be carefull with what you are offered as advice.

How's it all going over there?.. long time no see. Feel free to give me a call

[alijanjan 3]

Hi Glenn

Only if i was still in Auckland. i would have already seen you.

the problem is if i want to take it somewhere, i have to drive to Melbourne which is 300k drive. not sure how safe it is for the transmission to drive this much, what do you think. the other problem is i can probably find someone in Melbourne who has a scanner (just searching for bimmer mechanics on the net), but wouldn't be sure about having the brain ,

things are ok here but i miss NZ heaps and really like to come back if i could

Cheers

[alijanjan 3]

Had a test drive again and the transmission light comes on every time as soon as speed goes over 25-30k/h,

i scanned it again and this time comes up with code P1024

the car has gone crzy , forgot to mention that the fuel gauge also acts funny recently (last few weeks), i drive the car for 400k on a tank and still shows almost full

[gjm 3258]

P1024 again points to the VVT - "VVT-Self-Learning Function Faulty Lower Learning Range (Bank 1)"

Could just be coincidence that the fuel gauge (or more likely imo, the sender) is playing up.

[alijanjan 3]

After last night that the light was coming on every single time (tried more than 10times), I left the battery disconnected overnight and had a test drive today before going to work. The light never came back on!!!

[alijanjan 3]

After couple of days of driving I found out that if I start the car then put gear on "N" and rev up the engine to around 3k couple of times befor I put it on "D" and drive, the transmission light would not come on at all. Have tried it a lot, never comes on if I do it

Any idea?

By the way I got the battery place to test the battery as well, nothing wrong with it

[alijanjan 3]

Just an update on my case

10 days ago I changed the fluid and the filter, about 0.5 litter extra oil went in as well compare to what I got out of it

While doing this, I disconnected the main plug from transmission, it looked fine but I sprayed contact cleaner in it anyway

Since then I have driven about 1000 km and the light has not come back on at all, everything seems ok and all is working well. Hopefully it will stay this way

Thanks for all replies

Cheers