LSZ2 Stepping Motors - Headlight aim

W

wolverine2k

Member
 Hainault IG7
Hi all,

Ok so I'm onto the FINAL issue that I have with my car. The driver side headlight self adjustment just isn't working.

I bought a new stepping motor with the same part number 734 857-00 and when I first plugged it in, it seemed to work. Hooray I thought!

Bolted the headlight back up and tried the headlight again and... it's not working.

Checked ISTA+ and I have "LSZ2: Coils, stepping motors, faulty" showing up as an error code.

Tried plugging the old stepper motor into the connector and that seems to work now! So I swap them back and then... same thing. It works first time and then it won't work again and gives the same faulty stepping motor error!

Anyone have any idea what on earth is going on? I can't pass an MOT without this stupid headlight working. Could there be an issue with the main headlight wiring or could I have been supplied with a second dud stepping motor?

I rewired half the wiring to the stepping motor today and it made no difference. Total waste of time. So close yet so far...

Thanks!
 
If the motor doesn't work anymore, then you don't need it to self level. As an interim fix [or hack] you can re-adjust the whole headlight so the beam level is correct with the stepping motor stuck in whatever position its in. This will get you through the MOT? Will buy you some time to look into it more anyway.

I've got a stepping motor you can try, but would need it back. Also it assumes the one I've got is working. But then again it would be pretty weird for you to have 3 motors and none of them work if you see what I mean.
 
Oh actually I have a better idea... test the motors (both the ones you have) in your passenger headlight. This will prove whether they work or not.
 
kis said:
Oh actually I have a better idea... test the motors (both the ones you have) in your passenger headlight. This will prove whether they work or not.
Click to expand...

Good call! I'll try that and if not, I was actually thinking of unplugging them and adjusting manually as you suggested. It's so fiddly getting the connectors in/out of the headlight assembly. The last MOT failure did say:

Offside Front Headlamp levelling device inoperative (4.1.5 (a))
Offside Front Headlamp aim too low (4.1.2 (a))

If I take off both stepping motor plugs, will they still fail for "levelling device inoperative" as it'll be inoperative on both?

The offside headlamp adjusts to the correct position when I first plugged in the motor but then never adjusts again or does sometimes intermittently. Not sure why at all.

I have just bought a 3rd motor so thanks for the offer btw :)
 
[youtube]https://www.youtube.com/shorts/8osc644oDBA[/youtube]

Don't know if that clip is going to work. Youtube keeps uploading this as "shorts".

So the motors seize up and do nothing. The only way I can get them to work again is by either plugging them in upside down which seems to free them and then plugging them in the right way. But then they only work twice before seizing up again.

Definitely seems like two dodgy motors - I must be very unlucky as one of them was direct from BMW but stored on a shelf for quite a while...

I've ordered a second hand one to see before I return the BMW one.

This video was made on the driver side where I'm having issues. I'll try plugging into passenger side tomorrow and see what happens.
 
Just noticed that someone has broken the clips for the trim that surrounds the LCM.

I'm not sure what past repair works have been done on this car - could it be that the LCM itself is faulty? It sends a signal twice, the stepping motor definitely moves, and then stops sending signal as it's not hearing back?

Whoever has been on this car might have had a go at fiddling with the LCM connections possibly.
 
kis said:
Oh actually I have a better idea... test the motors (both the ones you have) in your passenger headlight. This will prove whether they work or not.
Click to expand...

Motors definitely work. Plugged them into passenger connector and they activate every single time. Driver side they either activate once or twice when plugged in and then never again.

The error code is at the LSZ so I've ordered a replacement switch from eBay... hopefully that will resolve it as I don't particularly want to trace the wiring all the way throughout the car looking for any breaks...
 
wolverine2k said:
Good call! I'll try that and if not, I was actually thinking of unplugging them and adjusting manually as you suggested. It's so fiddly getting the connectors in/out of the headlight assembly. The last MOT failure did say:

Offside Front Headlamp levelling device inoperative (4.1.5 (a))
Offside Front Headlamp aim too low (4.1.2 (a))

If I take off both stepping motor plugs, will they still fail for "levelling device inoperative" as it'll be inoperative on both?
Click to expand...

No problem!

I'm not sure, because other cars don't have the self leveling? They still pass. I think it was flagged due to one performing the action, and the other one not performing?

If you remove the motor, or even just disconnect the wiring at the headlight (so they stay static). You can adjust the lights so they are correct. Then it should all be fine?
 
wolverine2k said:
Just noticed that someone has broken the clips for the trim that surrounds the LCM.

I'm not sure what past repair works have been done on this car - could it be that the LCM itself is faulty? It sends a signal twice, the stepping motor definitely moves, and then stops sending signal as it's not hearing back?

Whoever has been on this car might have had a go at fiddling with the LCM connections possibly.
Click to expand...

LCM will trouble shoot whether its the LCM causing the issue. But will cause you more problems. Someone fried their LCM a while back. It means that you get an error code somewhere? Might even be a "tamper" code. You need to programme the LCM with you vehicle details, VIN, mileage, etc.

I've found the thread: https://z4-forum.com/forum/viewtopic.php?t=122365

Also regarding your original issue, I think the LCM can develop faults, so perhaps it was sent off for repairs? Like to ECU testing? They do a few bits for "our car" as its the same as the e46 (pretty much).

But yeah, if you've ordered an LCM, it will enable you to test the operation, so if it works, you know the issue is with the LCM. Not wiring, or anything else.
 
kis said:
No problem!

I'm not sure, because other cars don't have the self leveling? They still pass. I think it was flagged due to one performing the action, and the other one not performing?

If you remove the motor, or even just disconnect the wiring at the headlight (so they stay static). You can adjust the lights so they are correct. Then it should all be fine?
Click to expand...

You may have a point there... I'm going to go to my local mechanic who did the MOT last time and ask them if that'll work. I just need to figure out what to adjust the lights to as whatever bodge I do, they won't want to touch it :D

kis said:
LCM will trouble shoot whether its the LCM causing the issue. But will cause you more problems. Someone fried their LCM a while back. It means that you get an error code somewhere? Might even be a "tamper" code. You need to programme the LCM with you vehicle details, VIN, mileage, etc.

I've found the thread: https://z4-forum.com/forum/viewtopic.php?t=122365

Also regarding your original issue, I think the LCM can develop faults, so perhaps it was sent off for repairs? Like to ECU testing? They do a few bits for "our car" as its the same as the e46 (pretty much).

But yeah, if you've ordered an LCM, it will enable you to test the operation, so if it works, you know the issue is with the LCM. Not wiring, or anything else.
Click to expand...

A part number matching LCM was only £30 delivered next day so not too bad. I'll find out tomorrow if it resolves the issue as I now know both stepper motors are fine.

I'm aware of the tamper code, I changed an LCM on an E46 a long time ago and coded it back in fine so not too worried about that... only worry is that the E46 seemed to be easier to code than the E85 is or maybe I'm just getting too old and forgetting things :D

If it's not the LCM... then last resort is that I have to rewire the connector for the stepper motor. The cable goes into a big bundle though and then all the way to the bulkhead so it's not going to be a fun or easy job. Cheers for the link to that thread, I'll make sure that I keep the car disconnected while wiring!

By the way, I highly doubt the previous owner sent the LCM off for repair. Looking at the bodge jobs that I've had to fix, there's no chance he would have spent that kind of money on a repair!
 
How much of the wiring to the motor did you replace? mine had chafed through the insulation about 40cm back from the motor and the wire had corroded to the point that it only worked intermittently
 
G600 said:
How much of the wiring to the motor did you replace? mine had chafed through the insulation about 40cm back from the motor and the wire had corroded to the point that it only worked intermittently
Click to expand...

Where is 40cm? Does that take you to the engine bay? Or is that still inside the wheel arch?
 
kis said:
G600 said:
How much of the wiring to the motor did you replace? mine had chafed through the insulation about 40cm back from the motor and the wire had corroded to the point that it only worked intermittently
Click to expand...

Where is 40cm? Does that take you to the engine bay? Or is that still inside the wheel arch?
Click to expand...

It was about as far back as you can get from under the arch (liner out)
 
kis said:
I’ve had this saved on my phone. Hopefully it helps :thumbsup:
Click to expand...

I just saw those on mine! Thanks!!

Went to my MOT garage this morning and they said that they have to input the reg into the computer and the computer will tell them if they HAVE to test auto levelling or not...

Popping back just before lunchtime for them to put the car details on their computer and see (they were in the middle of an MOT at the time so couldn't check then).

G600 said:
kis said:
G600 said:
How much of the wiring to the motor did you replace? mine had chafed through the insulation about 40cm back from the motor and the wire had corroded to the point that it only worked intermittently
Click to expand...

Where is 40cm? Does that take you to the engine bay? Or is that still inside the wheel arch?
Click to expand...

It was about as far back as you can get from under the arch (liner out)
Click to expand...

So I only did up to where the cable splits out from the main headlight cable assembly. I guess I'll have to go much further back... I didn't fancy unravelling all that old black tape wrapped around the cables too far back :D

Today I sat the stepper motor on the floor and tried the switch and it worked. The headlight adjustment dial was working too... and then all of a sudden after 4 attempts of turning light on/off - it stopped working again. As there was literally no movement in the cables, would that still possibly be a wiring problem?

I've got other LCM arriving today which I am hoping is the issue rather than rewiring :D
 
It could be, mine would do strange things like go down and not come back up even if the car wasn't moving. I actually fixed one break in the cable near the light (thought I'd solved the problem but I hadn't) and then found another further back where it goes up against the chassis.
 
G600 said:
It could be, mine would do strange things like go down and not come back up even if the car wasn't moving. I actually fixed one break in the cable near the light (thought I'd solved the problem but I hadn't) and then found another further back where it goes up against the chassis.
Click to expand...

I went back to my garage and they said that they couldn't pass the MOT if I delete the self-levelling as they know it's there and also the manual levelling won't work anymore which is an MOT failure.

LCM didn't arrive today so didn't try that. I'll try and cut back the wires as far back as I can go on the weekend. I'll have to brake off the cable ties to loosen the cable to be able to get further down. If that doesn't solve it, my garage has said that they can replace the wiring... except I know they're going to rip me off.

Thanks!
 
LCM arrived... same issue. Definitely wiring then. Happy days. I'm making a real nice collection of parts that I never needed :D
 
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