Z4-forum.com

Hi guys,

Please help! My Z4 is driving me mad! Forgive the pun. I've just brought it out for the summer and it's all gone a bit crazy!

1. Sidelights work ok but switching to main beam switches on the full beam and I can't use the stalk switch to turn them off. The Blue full beam light remains lit on the dash. I can't flash the lights. So it's side lights (no blue light) or full beam (blue light). Nothing in between.

2. ABS, Handbrake Light, Tyre pressure light, traction control light all lit up in orange on the dash. I'm hoping it's all related. I've checked the tyre pressures as i understand it can create havoc if a tyre is badly under-inflated.

3. No response from the key fob. Alarm doesn't activate, doors don't lock/unlock. Fob seems ok. (Relays recently changed on the BCM (GM5) module.

I'm wondering if this bought of madness is all related and a module somewhere has freaked out. It still drives perfectly (but clearly no ABS) so it's such a shame it's being a pain in the arse especially now the weather is finally breaking!

Please please help before I shove it into a lake!

Always worth maybe checking the battery, a low charge on it can cause all sorts of problems.

Do you have a code reader? That would help you identify issues and get error codes off the car. Maybe someone local might have one, or just buy one off Amazon they are around 50 quid.

As above, battery health first.
If not that then possibly separate issues.

1. Lights could be a fault in the stalk on the steering column.
2. With all four of those lights on it is most oftern an ABS sensor. A good code reader would tell you which one.
3. If the GM5 has been repaired then most likely a dead battery in the key fob. try leaving it overnight on a toothbrush charger. Failing that you'll need to get the battery replaced.

It's also possible that the lighting issues are related to a duff Lighting Control Module (the bit behind the switch). I replaced mine recently after some weirdness (no lighting controls, sidelights permanently on), for £30 for a used part and 10min of fitting.

Agree with the poster above, the dash lights you describe point to a duff ABS sensor. £30 on a code reader will tell you which one it is, or a competent garage could do the same in about 5min.

Regarding code reading, see if anyone here is near you (Just skip to the last post )
viewtopic.php?t=144268

Where you based?

Issue 1 I’d say is either a slip ring or lcm issue
Issue 2 is abs sensor
3 as above recharge or re link key

Eminently fixable don’t push it in a lake yet

I don't think I could launch it into a lake as I love the thing when it's behaving.

I've tried charging the key fob on a toothbrush charger and re-linking the key but it is completely unresponsive. A bit more information about this... It was possible to unlock the driver's side door with the key, get in, close the door, insert the key in the ignition and turn on, then press the door unlock button until the buttons popped up then open the passenger's side. Now though, that doesn't work and it isn't even possible to open the passenger's side at all! I don't know if this sheds any more light on things?

What is a slip ring? And the LCM is behind the rotary switch for the lights?

Thank you so much guys! I really appreciate your comments.

If it was working before hibernation then I doubt anything has gone wrong just sitting there. My bet would be the battery.

mixtli wrote: ↑Tue Mar 26, 2024 6:53 pm What is a slip ring? And the LCM is behind the rotary switch for the lights?

My guess is poor battery health too. First thing, charge it up then clear the codes. If you are not close to anyone with a code reader, then a Creator C310+ is a great investment at c.£50.

Slip ring is the part of the steering column that the indicator stalks are attached to, also known as clock spring.
LCM is indeed behind the light switch.

Hope you get it sorted soon.

Fit a good battery (new) first action, second check for evidence of rodents, mice, rats, squirrels, cancel the codes and see what comes back

deltasierra wrote: ↑Tue Mar 26, 2024 7:49 pm second check for evidence of rodents, mice, rats, squirrels, cancel the codes and see what comes back

That is a good shout IMO. Those little feckers can nibble through insulation so easily and create 'dead shorts' on a myriad of sensitive cabling.
A good place to start to see if you have had visitors is anything with foam around it. They like that cos it's warm, easy to rip and good to make nests with.

If issue 2 isn’t an ABS sensor, if I recall correctly it could be the yaw sensor that lives underneath the carpet in front of the passenger seat. Mine was the same unit as used in Mini’s so was £25 from eBay.

But as above code read first.

Good luck.

McSwerve wrote: ↑Fri Mar 29, 2024 7:14 am If issue 2 isn’t an ABS sensor, if I recall correctly it could be the yaw sensor that lives underneath the carpet in front of the passenger seat. Mine was the same unit as used in Mini’s so was £25 from eBay.

But as above code read first.

Good luck.

The yaw sensor doesn’t usually put the tyre light on, though of course that could be a separate issue of a tyre being low

After a good amount of digging through the fault codes, the abs sensor on the front passenger side is kaput so that's an easy fix.

Not much illuminated by trying to find a problem with the lights (please forgive the pun??!). I want to replace the LCM as it's easy and cheap enough to eliminate but as usual, I have a question. Does the part number of the LCM have to match exactly? I realise I can't replace my 'non-automatic lights' version with one that has automatic lights but what else might I have to loo out for. Nothing I can't find for sale has a part number like mine but the units look identical.

To add to my woes, a could spring snapped a couple of days ago taking the top mount out too. A new shock, mount and spring on their way.