Automatic Transmission Warning Light

UK forum for general and technical discussion about the Z3 roadster
Post Reply
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Automatic Transmission Warning Light

Post by chris.sargent »

Hi, I've just changed the radiator on a 1999 2.8 Z3 and since you have to take the transmission lines off, I lost some ATF. On starting the car the transmission warning light came on.

Will the light come on if it the AT oil level is too low?

(I'm not sure if it's shifting as normal at the moment as it's still very slippery outside and I didn't fancy the test drive!)
trackdaywidow
Joined: Sat 05 Jan, 2008 16:06
Posts: 66

  Not specified
Location: Bedford

Post by trackdaywidow »

did you top the fluid back up?
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Post by chris.sargent »

Not yet.
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Post by chris.sargent »

An update. The car has been sat for almost two weeks not used and went in to Harpenden Auto Services this morning to have it's automatic fluid changed. On driving to the garage the warning light was still on and the gearbox was pretty clunky, particularly when changing down gears or changing from 2nd to 3rd. The journey is only 5 miles and the clunking started on the first gear change (the car has not been driven since I thought it was low on transmission oil).

HAS have changed the transmission oil but the warning light did not go away and the clunking is still very much apparent. They looked up the fault and it came back as a CAN Data error. They cleared the fault but it came back again straight away. Unfortunately, we didn't have time to delve in to the problem deeper but will hopefully get it booked in again in the next few days. The garage said they would probably start by resetting the adaptations which I guess could help but I am slightly sceptical.

Does anyone have any ideas why the gearbox might have gone like this from changing the radiator which included disconnecting and reconnecting the transmission oil cooling lines. It can only have lost 0.5l of fluid at most and since the clunkiness started straight away, I can't imagine it's anything that's suddenly worn out immediately.

Does anything in the transmission fluid system need bleeding?
estocks
Joined: Tue 04 Oct, 2005 23:36
Posts: 2866

  Not specified

Post by estocks »

I think the transmision takes about 11L, so that ~0.5L might not be significant. You never know how low the oil goes before the light comes on. It certainly sounded like it needed some oil, or that more than 0.5L was lost.

To change the oil you need to power flush it, not just drain it, and the oil must be between 30 and 50C.

CAN error wouldn't surprise me, since you don't have a CANBUS car, you have the older KKL interface.
Useful link on the ZF gearbox.
Image
Use the Search button before posting newbie questions about hard tops and fitting kits, footwell speaker amps, water in the boot, hood maintainance and those horrific angel eyes. We get like 10 threads a week on the same subject, it's obvious that you haven't searched.
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Post by chris.sargent »

cheers for the reply. My car doesn't have the ZF box, it's the 4-Speed GM A4S270/310R. I didn't do the fluid change myself but the oil would have been warm as I'd just driven the car to them. It wasn't powerflushed, just drained and topped up - looks like they put in about 4 litres of oil. I don't see how that would affect it though?
estocks
Joined: Tue 04 Oct, 2005 23:36
Posts: 2866

  Not specified

Post by estocks »

On the ZF (speaking from experience), about 2L of oil is retained in the torque convertor. Mixing 150k mile oil with new stuff can lead to problems, according to some scare stories. As you have 10-20% of the old oil left inside, another change will give you 1-5%, a much better number.
Image
Use the Search button before posting newbie questions about hard tops and fitting kits, footwell speaker amps, water in the boot, hood maintainance and those horrific angel eyes. We get like 10 threads a week on the same subject, it's obvious that you haven't searched.
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2092

  Z3 roadster 2.8
Location: Daglan, France

Level

Post by Mike Fishwick »

According to the BMW TIS, oil level is very critical, a few mm change being necessary for a small change in oil temperature, the result being rattles fom the control valves, which may be your 'clonks.'

I would have measured the amount of oil spilt, and topped up with the same volume of new ATF.

Hopefully your problem is a combination of low oil level and low ambient temperature.

If HAS cannot find the problem, try a real auto box specialist. BMW do not supply much information about the auto boxes, dealers using the well-known 'Let's fit a new one and see what happens' technique - at the customer's expense, of course!
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Post by chris.sargent »

A further update on this:

The engine is reporting a faulty MAF sensor and the computer is not seeing any output from it at all.... bit strange as I can't see how changing a radiator could affect this but hey ho... that's put the car in to limp mode - could explain the strange gearbox behaviour.

A new MAF has been ordered and should be fitted tomorrow to see if it cures the faults.
User avatar
chris.sargent
Joined: Fri 29 May, 2009 11:27
Posts: 69

  Z3 roadster 2.8

Post by chris.sargent »

Just thought I'd post my solution to this... Had a new MAF fitted and all is well... engine codes have gone and gearbox is behaving! That's one strange coincidence...! It's interesting that the faulty MAF caused the gearbox light to come on rather than the EML but there you go!?!

Seems it's got a faulty exhaust cam sensor and a broken crankcase ventilation valve.... can't say I'm looking forward to changing them after reading some of the DIYs!
coquitlam glenn
Joined: Wed 20 Sep, 2023 13:04
Posts: 1

  Z3 roadster 1.9i

Re: Automatic Transmission Warning Light

Post by coquitlam glenn »

This dead thread saved me. I had the exact same problem. Changed my MAF, right before I replaced the front shocks. So, the car sat over the weekend while I completed it. I started it up, and the dreaded tranmission warning light came on. I topped up the trans fluid (it leaks), thinking it was triggered by low fluid. Restarted the car, light didn't go away. Took it for a test drive and it was running rough, plus the transmission was hard-shifting. I tried everything I could think of...bought a code reader to clear the code but it reported no issues with the transsmission. Nothing made sense.

Then I stumbled on this thread. It had not occurred to me that the MAF could possibly be the issue. I swapped the old MAF back in and presto, all the issues went away and the warning light went out. This also explains the clean report from the code-reader.

The take-away for me: Limp mode will cause the transmission shift hard and the transmission light to come on. However, the issue that triggers the limp-mode can have nothing to do with the trans at all. Weird...
LaRy
Joined: Mon 12 Nov, 2018 17:47
Posts: 149

  Z3 roadster 2.8

Re: Automatic Transmission Warning Light

Post by LaRy »

I had good contact with a BMW experienced technician, now retired. It happened sometimes that I discussed fault codes. His comment was that this is a car with very early CAN-bus communication. Different units from different manufactures has different protocols, and they tried to make it work as good as possible together. Sometimes it doesn't work, giving false information. This is not like new car. Faultcodes, yes it gives some information, but always doublecheck the component by multimeter if it is true.
My best example: ABS/ACS problems showing fault code 32, ABS sensor right front wheel no signal. In fact, it was the ABS/ACS relay! The technician told me that if you get faults like abs sensor right front wheel, double check it with a mutimeter. Don't just trust it and order a new one.
Post Reply