Help Appreciated: Fault Codes & Airbag Light

[Abbas]

Evening all,

Good news: I am now the proud owner of a black Z4MR!
Bad news: I am now the proud owner of a black Z4MR!

Attaching the only picture I've took so far

I'm really looking forward to getting to know the S54, I've had an "M" itch for a while. However, typical with my luck, I have a few little niggles I need to get seen to before I can really start to enjoy it without any anxiety. I would very much appreciate your help and advice on the faults.

A bit of background and context:
Last weekend I part ex'd my 3.0si coupe towards a Z4MR from a dealership. I'm by no means a mechanic, but I did all due diligence on my part when viewing the car, and it ticked all the boxes. Great condition, no knock sounds etc when the engine was fired up, history of vanos maintenance, paperwork, recently had an Insp2 done, took it for a test drive. Happy days. As luck would have it, it's only when I paid for it and drove off I got an airbag light I rang the dealership and took it back, and to be fair, really nice guys. They said most likely the battery's low on charge / struggling to charge, as they charged it up the day before I came. It had been sat at the dealership since around January I believe. It was a Saturday so most garages were shut, and I was miles from home and had to get going so we agreed that I'd take it to a garage I trust near me during the week and they'd sort me out for a new battery.

Drove absolutely fine on the way back from Scotland. Very comfy, pleasant place to be. My brother used his car tablet thing and had a look. Found a few fault codes, he tried to reset the airbag light, but it came back on again once I got down the road. He had a look at the battery and it seemed a little low on voltage but not awful. 11.8 volts I believe. Not sure if them being a little on the low side upsets Z4's? Anyway next day I drove about 90 mins away to meet some Z4 friends from here actually! Barty and Joel At The Cat and Fiddle. I thought it might help charge the battery aswell. Once I said bye to them, I hopped back in and started giving it the beans, and just when I started having a giggle and enjoying myself, I then got an engine management light! So I parked up and thought maybe if I turn it off and on, it'll go away it didn't, but it was now struggling to turn over and fire up. So I took it easy on the way home, and figured it looks like the battery actually was on the way out.

I took it to the garage the next day, funnily enough it fired up just fine this time before setting off. They tested the battery, and it actually seems in OK health, little low on voltage but no red flags. Same as my brother said. Tried to reset the airbag light, and that disappeared for a bit and then came back. When resetting the engine codes, it now struggled to start up again. The EML hasn't come back since, and the engine fires up fine again, however the engine fault codes remain. The garage said hopefully it's just sensor issues and not a timing issue (fault codes below) - not a clue what that means, but I hope it's fixable either way. Rang the dealership and they said my warranty will look after the work required based on the fault codes, so I'm booked in with the garage next week. This takes the edge off a bit as I don't want to foot the bill on a car I've just bought and was advertised as pristine.

For the airbag light / fault code: - I've searched online for this a little bit and got different views on it. But it seems a passenger sensor pad is a common issue for throwing up an airbag light? Would there be anything in that? And would it link to the fault code for the passenger heating element? My brother said the passenger seat seems to warm up slower according to his car tablet, so was wondering if this is linked and perhaps an element or something is slightly knackered on it? Does it get confused when someone sits on the passenger seat? I mention this because when having a nosey around the car at the dealership and firing it up - zero warning lights. When firing it up after the test drive and going home, the airbag light was now on. Only thing that had changed was the fella from the dealership had sat in the car while we went for a test drive. Had that upset it?

Roof doesnt work: When it rains it pours! Not sure if this is related, but the roof also decided to stop working last time I hopped in too. Was fine before, and even wit the airbag warning light. When pressing the roof down button, the light comes on, but nothing happens. No light when pressing the roof up button. Not sure if this is related in any way, or is a separate issue with a fuse or a roof motor which needs relocating as it has been parked on the drive and it's been raining a fair bit past few days. Hopefully it's something the ZedShed can sort if it's a separate issue.

I've attached the fault codes below... I wanted to post it on here and see if you had any thoughts and advice I can pass on to the garage for when they work on it next week. They're very good mechanics but not E85 specialists specifically so if they struggle with it, I'll take it to a Zed specialist and make use of the warranty while I can.

More positive news: I'm pleasantly surprised with fuel economy on the Z4M. It's actually better than my si was by 1mpg. I'll take that. It's just as comfortable as the coupe was around town, which was key for me, So I'm really hoping I can get these bits sorted and start to really enjoy the car. The dealership also threw in a GruppeM intake for cheap that they took off, so very excited to get that fitted as well once the cars in rude health.

Thank you for reading. Over to you guys

Abbas

[enuff_zed]

Good morning and congratulations.

It looks to me like step one is replace the camshaft sensors (do inlet as well), and the crankshaft sensor.

There is a chance these are also what is causing the DME not to talk to the DSC module as it is not getting all the info it needs, but you won't know until you change them.
If not then you may have an issue with the DSC module. These can be removed and reconditioned by ECU Testing for £189.

No experience with seat heating. Usel may be able to advise?

The airbag module on the facelift is different and cannot be easily swapped and coded as the earlier models can. I would check the connections to the steering wheel bag and the drivers door bag before going further. Make sure the retaining clips on the plugs are still fitted.
If it turns out to be ASCM module itself then I think you will need to find one with exactly the same part number and get it cloned.
slippershoe is going through exactly this with his M right now, so may be able to give some input.

Oh, and regarding the roof motor: obviously it needs to come out to be sorted. A garage is likely to remove the whole roof and then put it back in the same place. This means you still have the same potential future issue.
They also often forget to overfill the reservoir. They only fill to the mark and of course the system then self bleeds and the level drops. I've had two like that that worked once then stopped again.
Plenty of people on here who can relocate it for you.

[j3nks79]

It would be very unlikely that all 3 sensors have failed.
2 cam and 1 crank. So don’t start throwing money at sensors just yet.
I would double check the battery as low voltage will cause you all sorts of trouble.

[Abbas]

Good morning and congratulations.

It looks to me like step one is replace the camshaft sensors (do inlet as well), and the crankshaft sensor.

There is a chance these are also what is causing the DME not to talk to the DSC module as it is not getting all the info it needs, but you won't know until you change them.
If not then you may have an issue with the DSC module. These can be removed and reconditioned by ECU Testing for £189.

No experience with seat heating. Usel may be able to advise?

The airbag module on the facelift is different and cannot be easily swapped and coded as the earlier models can. I would check the connections to the steering wheel bag and the drivers door bag before going further. Make sure the retaining clips on the plugs are still fitted.
If it turns out to be ASCM module itself then I think you will need to find one with exactly the same part number and get it cloned.
slippershoe is going through exactly this with his M right now, so may be able to give some input.

Oh, and regarding the roof motor: obviously it needs to come out to be sorted. A garage is likely to remove the whole roof and then put it back in the same place. This means you still have the same potential future issue.
They also often forget to overfill the reservoir. They only fill to the mark and of course the system then self bleeds and the level drops. I've had two like that that worked once then stopped again.
Plenty of people on here who can relocate it for you.

It would be very unlikely that all 3 sensors have failed.
2 cam and 1 crank. So don’t start throwing money at sensors just yet.
I would double check the battery as low voltage will cause you all sorts of trouble.

Thank you both. Yeah I might mention to the garage just stick in a new battery anyway, I’m not paying for it personally so may aswell get a new battery out of it and as you say, it can’t hurt and may fix a few issues. And they can take it from there.

In either case, Hopefully the fault codes aren’t too severe, that was my main concern

The airbag light seems to be abit intermittent. Brother cleared the fault code again yesterday and it’s not come back on since, and I’ve took it out a couple times. I’m expecting it to appear again at some point. Strange.

[Mr Tidy]

Congratulations on scratching your M itch.

I did the same and 4 years on I'm still loving it!

Sorry I can't help with your codes but I got 3 random warning lights on mine due to a dying battery, so hopefully that's what has happened to yours too.

[enuff_zed]

It would be very unlikely that all 3 sensors have failed.
2 cam and 1 crank. So don’t start throwing money at sensors just yet.
I would double check the battery as low voltage will cause you all sorts of trouble.

Well , I just thought they were so cheap and easy, why not?

[j3nks79]

It would be very unlikely that all 3 sensors have failed.
2 cam and 1 crank. So don’t start throwing money at sensors just yet.
I would double check the battery as low voltage will cause you all sorts of trouble.

Well , I just thought they were so cheap and easy, why not?

Because it’s highly unlikely that all 3 sensors have failed/failing at the same time.
If it was a code for just 1 sensor then yeah replace it.

If it’s not low voltage causing the errors then I would be looking at timing first for those errors.
Possible dry solder joints in the vanos solenoid valve pack. Very common on the S54 for bringing up those codes.
But hey let’s not jump the gun just yet. And start from the beginning

[slipperyshoe]

As mentioned I have a similar situation since mine sat without charge and was jumped multiple times. So far I’ve replaced the module (which are apparently coded to the car but the matching part number appears to have worked) but I’ve got two new fault codes relating to the airbag deactivation switch and telltale passenger airbag off (93D2, 93BE). Hoping to have someone have a look over the weekend with more of an idea than me so will keep you posted. It may be that I’ve stilll got a module that’s not coded properly, or I might have another issue. So basically I’m afraid I’m not much help!

As you said, often a fault is pointed at the mat sensor. Someone in an older thread quite logically suggested having a passenger sit in the seat with no seat belt. Once you hit 10-15mph the seatbelt sign should come on if it’s working. Seemed like a good suggestion to check it the analogue way!

[Usel]

The airbag light could be related to the steering wheel airbag.

Start with the passenger seat first as you have a problem there also.

Top down, if you have electric seats remove the 4 nuts/bolts for the seats rails and the bolt for the seat belt, disconnect the battery and wait 30 minutes. Unclip the seat belt from the shoulder clip whilst waiting. After 30 mins remove the wire harness under the seat.

Lift the seat out.

Under the seat you'll find this:

20240505_074548.jpg (118.03 KiB) Viewed 215 times

If you have electric seats there will be a block connector on the left. The heated seat connector is on the right with red, blue, yellow dots.

Circled purple is for the occupancy sensor mat, circled green is for the seat belt clip and circled orange is for the pretensioner.

Do not put a multimeter on the pretensioner circled orange unless you know what you're doing. It could fire off the charge.

Clean all the pins with contact cleaner or isopropanal alcohol. Do not use WD40 or similar.

On the heated seat connector red and blue are the heat pads circuits and yellow is the temperature sensor wire. If the temperature sensor wire is faulty you'll get a flashing light on the heated seat button.

Put a multimeter on the red and blue pins and do a continuity check. You should get a low resistance reading of 005 or similar, much higher and you have problems. If higher follow the wires back and you'll find you can split the back rest and seat base elements. Now resistance check those separately to check the readings.

This bit is optional, get familiar with the under seat yellow block connector. Slide the yellow block off the seat support, cut the cable tie off wire support, slide the black cap off the top which exposes the back of the connectors. Pull the black connector blocks out and push them back in.

Now when the seat is back in the car you can fiddle with the yellow block connector knowing how it works.

Put the seat back in, connect everything and then connect battery.

Try and clear the airbag light. Now test the seat heating and occupancy sensor by going for a drive like slippery shoe above has said.

Now read the codes.

If same fault codes for airbag you can try the following.

Disconnect battery. Wait. Pull out yellow connector, pull out purple circled block connector and leave it out. Connect everything back together. Connect battery. Now check codes. Do you get more fault codes? If no then it's the occupancy sensor.

If yes then the occupancy sensor is fine and plug it back in. Whilst there remove the pins circled orange, isolate them separately with tape and connect back up. Again check for fault codes.

If you get no extra codes then it's faulty. If you get no extra codes then something else is causing the airbag fault.

It will be a lot easier if you cam get hold of a known working seat and just swap them out. Needs to be a facelift seat. Doesn't need to be a M-Sport seat.

[paddy wright]

Where are you based?

[Abbas]

The airbag light could be related to the steering wheel airbag.

Start with the passenger seat first as you have a problem there also.

Top down, if you have electric seats remove the 4 nuts/bolts for the seats rails and the bolt for the seat belt, disconnect the battery and wait 30 minutes. Unclip the seat belt from the shoulder clip whilst waiting. After 30 mins remove the wire harness under the seat.

Lift the seat out.

Under the seat you'll find this:

20240505_074548.jpg

If you have electric seats there will be a block connector on the left. The heated seat connector is on the right with red, blue, yellow dots.

Circled purple is for the occupancy sensor mat, circled green is for the seat belt clip and circled orange is for the pretensioner.

Do not put a multimeter on the pretensioner circled orange unless you know what you're doing. It could fire off the charge.

Clean all the pins with contact cleaner or isopropanal alcohol. Do not use WD40 or similar.

On the heated seat connector red and blue are the heat pads circuits and yellow is the temperature sensor wire. If the temperature sensor wire is faulty you'll get a flashing light on the heated seat button.

Put a multimeter on the red and blue pins and do a continuity check. You should get a low resistance reading of 005 or similar, much higher and you have problems. If higher follow the wires back and you'll find you can split the back rest and seat base elements. Now resistance check those separately to check the readings.

This bit is optional, get familiar with the under seat yellow block connector. Slide the yellow block off the seat support, cut the cable tie off wire support, slide the black cap off the top which exposes the back of the connectors. Pull the black connector blocks out and push them back in.

Now when the seat is back in the car you can fiddle with the yellow block connector knowing how it works.

Put the seat back in, connect everything and then connect battery.

Try and clear the airbag light. Now test the seat heating and occupancy sensor by going for a drive like slippery shoe above has said.

Now read the codes.

If same fault codes for airbag you can try the following.

Disconnect battery. Wait. Pull out yellow connector, pull out purple circled block connector and leave it out. Connect everything back together. Connect battery. Now check codes. Do you get more fault codes? If no then it's the occupancy sensor.

If yes then the occupancy sensor is fine and plug it back in. Whilst there remove the pins circled orange, isolate them separately with tape and connect back up. Again check for fault codes.

If you get no extra codes then it's faulty. If you get no extra codes then something else is causing the airbag fault.

It will be a lot easier if you cam get hold of a known working seat and just swap them out. Needs to be a facelift seat. Doesn't need to be a M-Sport seat.

As mentioned I have a similar situation since mine sat without charge and was jumped multiple times. So far I’ve replaced the module (which are apparently coded to the car but the matching part number appears to have worked) but I’ve got two new fault codes relating to the airbag deactivation switch and telltale passenger airbag off (93D2, 93BE). Hoping to have someone have a look over the weekend with more of an idea than me so will keep you posted. It may be that I’ve stilll got a module that’s not coded properly, or I might have another issue. So basically I’m afraid I’m not much help!

As you said, often a fault is pointed at the mat sensor. Someone in an older thread quite logically suggested having a passenger sit in the seat with no seat belt. Once you hit 10-15mph the seatbelt sign should come on if it’s working. Seemed like a good suggestion to check it the analogue way!

Where are you based?

Thank you all! I’ll definitely try that seat belt trick today. Really appreciate the write up Usel. It’s probably beyond my skill set, I’ll break something so I’ll print it off for the garage and they can give it a follow.

Paddy - I’m based in Huddersfield, West Yorkshire

[Simon 3.2M]

Personally I would look at replacing the battery and getting the voltage regulator checked as this will throw the car all over the place!! Mine had an uneven idle and it would hunt from time to time and the voltage was dipping in sympathy. Had the regulator checked and it was fine however, I trusted my gut and changed it - no problems since.

A word of advice, start with the easiest things first, as mentioned don’t go splashing cash on expensive sensors.

As these cars are so susceptible to battery / voltage fluctuations, start you investigations there.

PM me your number if you’d like to discuss further.

[Abbas]

Personally I would look at replacing the battery and getting the voltage regulator checked as this will throw the car all over the place!! Mine had an uneven idle and it would hunt from time to time and the voltage was dipping in sympathy. Had the regulator checked and it was fine however, I trusted my gut and changed it - no problems since.

A word of advice, start with the easiest things first, as mentioned don’t go splashing cash on expensive sensors.

As these cars are so susceptible to battery / voltage fluctuations, start you investigations there.

PM me your number if you’d like to discuss further.

Thanks Simon! I’ll definitely suggest to the garage to stick a decent new battery in and they can take it from there. Hopefully it solves the niggles. That would be a result

As far as battery’s go, do you have any recommendations? Halfords and the Yuasa website points me to a fancy start/stop one. I don’t need that do I?

[Mr Tidy]

No, you don't need an AGM battery on your car - and a new one doesn't need coding.

I bought an Exide from Tayna for my MC for £104.97 in April 2021. It was actually an AGM but that's because I read on here they might be better for a car that wasn't used frequently.

Then I took it to Ross at RBM Hampshire and after he reset the steering angle sensor the 3 amber lights went out!

[paddy wright]

The airbag light could be related to the steering wheel airbag.

Start with the passenger seat first as you have a problem there also.

Top down, if you have electric seats remove the 4 nuts/bolts for the seats rails and the bolt for the seat belt, disconnect the battery and wait 30 minutes. Unclip the seat belt from the shoulder clip whilst waiting. After 30 mins remove the wire harness under the seat.

Lift the seat out.

Under the seat you'll find this:

20240505_074548.jpg

If you have electric seats there will be a block connector on the left. The heated seat connector is on the right with red, blue, yellow dots.

Circled purple is for the occupancy sensor mat, circled green is for the seat belt clip and circled orange is for the pretensioner.

Do not put a multimeter on the pretensioner circled orange unless you know what you're doing. It could fire off the charge.

Clean all the pins with contact cleaner or isopropanal alcohol. Do not use WD40 or similar.

On the heated seat connector red and blue are the heat pads circuits and yellow is the temperature sensor wire. If the temperature sensor wire is faulty you'll get a flashing light on the heated seat button.

Put a multimeter on the red and blue pins and do a continuity check. You should get a low resistance reading of 005 or similar, much higher and you have problems. If higher follow the wires back and you'll find you can split the back rest and seat base elements. Now resistance check those separately to check the readings.

This bit is optional, get familiar with the under seat yellow block connector. Slide the yellow block off the seat support, cut the cable tie off wire support, slide the black cap off the top which exposes the back of the connectors. Pull the black connector blocks out and push them back in.

Now when the seat is back in the car you can fiddle with the yellow block connector knowing how it works.

Put the seat back in, connect everything and then connect battery.

Try and clear the airbag light. Now test the seat heating and occupancy sensor by going for a drive like slippery shoe above has said.

Now read the codes.

If same fault codes for airbag you can try the following.

Disconnect battery. Wait. Pull out yellow connector, pull out purple circled block connector and leave it out. Connect everything back together. Connect battery. Now check codes. Do you get more fault codes? If no then it's the occupancy sensor.

If yes then the occupancy sensor is fine and plug it back in. Whilst there remove the pins circled orange, isolate them separately with tape and connect back up. Again check for fault codes.

If you get no extra codes then it's faulty. If you get no extra codes then something else is causing the airbag fault.

It will be a lot easier if you cam get hold of a known working seat and just swap them out. Needs to be a facelift seat. Doesn't need to be a M-Sport seat.

As mentioned I have a similar situation since mine sat without charge and was jumped multiple times. So far I’ve replaced the module (which are apparently coded to the car but the matching part number appears to have worked) but I’ve got two new fault codes relating to the airbag deactivation switch and telltale passenger airbag off (93D2, 93BE). Hoping to have someone have a look over the weekend with more of an idea than me so will keep you posted. It may be that I’ve stilll got a module that’s not coded properly, or I might have another issue. So basically I’m afraid I’m not much help!

As you said, often a fault is pointed at the mat sensor. Someone in an older thread quite logically suggested having a passenger sit in the seat with no seat belt. Once you hit 10-15mph the seatbelt sign should come on if it’s working. Seemed like a good suggestion to check it the analogue way!

Where are you based?

Thank you all! I’ll definitely try that seat belt trick today. Really appreciate the write up Usel. It’s probably beyond my skill set, I’ll break something so I’ll print it off for the garage and they can give it a follow.

Paddy - I’m based in Huddersfield, West Yorkshire

I’m in Penistone if you want to come over I have a code reader