Multiple electrical issues on my BMW Z4

[zeah555]

Hey everyone, I got myself a BMW Z4 2003 3.0i earlier with 100k miles on it. When I got the car, the brake pad, tire pressure, and the airbag light was on. I figured it was probably just a fuse/sensor so I didn't mind it as much. I also noticed that the radio is stuck on "PHONE" and I can only switch between that and the clock.

It bothered me a little bit because I want some music on my car, found a forum post that said I just have to remove the radio fuse and then put it back on. So this is what I did exactly, removed fuses 47, and 50. I turned on the car with the fuses removed, then turned off the car, put the fuse back in, then started the car. It didn't resolve the radio stuck on phone issue but now new problems arose, here's a list of them.

- Turn signal lights work but green arrow does not light up and no clicking sound, I just noticed the lights were still working through the reflection.
- I can't put the roof down anymore, the button lights up red as I press the button then immediately goes away as soon as I stop pressing the button. It does not flicker like other people's issue.
- My remote key doesn't work anymore. I can't unlock/lock the door using the remote. I have to manually unlock/lock the door.
- After starting the car, if I turn off the engine then remove the key, the cluster lights remain turned on, no warning lights or anything, only the speedometer and the gauges. Took me a couple of tries restarting the car to get them to turn off.

After a while my remote key suddenly works again. But after testing out the car again, as i step out of my vehicle, the remote key will stop working again. Then after a while, it will work again lol.

I really need help, what are your thoughts? Do you think it could be the battery or another fuse? If possible, can you also help me out with the brake pad, tire pressure, and airbag lights? Thanks for helping me out.

[enuff_zed]

Hi.
You really need the codes read first.
Look for codes mentioning K-bus as any issues with one module on that system can affect loads of other stuff, including the issues you have with the instruments and locking.
With the airbag light being on it sounds similar to a fault I have dealt with 3 times now. On each occasion it was the centre airbag module having water ingress, causing faults all round the K-bus circuit.
Get the codes and work from there

[zeah555]

Thanks for the reply! I'm gonna be honest with you, I'm a beginner at fixing car issues. I only know the basics. I don't have a scanner yet but I just ordered this from Amazon, it'll arrive later. https://a.co/d/bsr1j4J

[Reamesy]

Might sound daft but have you definitely put the two fuses back in the correct location. I’ve seen similar before as there are often spare slots. Very easily done.

It’s worth a check as the other faults were not there.

Also get a code reader and pay attention to wheel speed sensor. If they go (one on each wheel hub) then they knock out all other systems that take readings I.e. ABS, traction control.

Basic code readers can be as little as £30-50

[enuff_zed]

zeah555, are you in the UK? If so, whereabouts.
A few of us about who could lend a hand.

[zeah555]

Might sound daft but have you definitely put the two fuses back in the correct location. I’ve seen similar before as there are often spare slots. Very easily done.

It’s worth a check as the other faults were not there.

Also get a code reader and pay attention to wheel speed sensor. If they go (one on each wheel hub) then they knock out all other systems that take readings I.e. ABS, traction control.

Basic code readers can be as little as £30-50

I just ordered this one from amazon: https://a.co/d/bsr1j4J

zeah555, are you in the UK? If so, whereabouts.
A few of us about who could lend a hand.

Unfortunately though, I'm in the US. Washington state


As soon as the scanner arrives, I'll hook it up to my computer and scan for codes.

[enuff_zed]

Might sound daft but have you definitely put the two fuses back in the correct location. I’ve seen similar before as there are often spare slots. Very easily done.

It’s worth a check as the other faults were not there.

Also get a code reader and pay attention to wheel speed sensor. If they go (one on each wheel hub) then they knock out all other systems that take readings I.e. ABS, traction control.

Basic code readers can be as little as £30-50

I just ordered this one from amazon: https://a.co/d/bsr1j4J

zeah555, are you in the UK? If so, whereabouts.
A few of us about who could lend a hand.

Unfortunately though, I'm in the US. Washington state


As soon as the scanner arrives, I'll hook it up to my computer and scan for codes.

OK, well I suggest you read the codes, but bear in mind there could be old ones still in there, so note every one, then try to clear and see what you are left with.
Then come back with both lists and we'll see what we can work out.

[zeah555]

Hey everyone, so I found the problem and fixed a couple of them.

1. I removed the Airbag fuse and accidentaly placed it on a different slot with no power. Returned it to where it belongs and now my turn signals work fine, roof also works now (I don't know how that's connected to airbag fuse tho).

2. Solved the remote not working by leaving the car on for almost an hour. Also charged it for a bit. The battery was drained since it hasn't been driven on the car dealership for a while, also because it's winter.

3. I finally got the scanner and almost resolved all warning lights, airbag lights cleared, tire pressure cleared.

All that's left now is the Brake pad sensor, I don't see an option to clear it from my scanner. Any thoughts? Thanks!

[enuff_zed]

Hey everyone, so I found the problem and fixed a couple of them.

1. I removed the Airbag fuse and accidentaly placed it on a different slot with no power. Returned it to where it belongs and now my turn signals work fine, roof also works now (I don't know how that's connected to airbag fuse tho).

2. Solved the remote not working by leaving the car on for almost an hour. Also charged it for a bit. The battery was drained since it hasn't been driven on the car dealership for a while, also because it's winter.

3. I finally got the scanner and almost resolved all warning lights, airbag lights cleared, tire pressure cleared.

All that's left now is the Brake pad sensor, I don't see an option to clear it from my scanner. Any thoughts? Thanks!

Good work so far.
If the brake wear sensor has activated then it’s saying you need new pads. Once it’s been activated you need to fit a new one.

[zeah555]

Carfax says the brake pads and sensors were just replaced last month. Do you think it wasn't installed properly? Or is there something that I need to reset?

Good work so far.
If the brake wear sensor has activated then it’s saying you need new pads. Once it’s been activated you need to fit a new one.

[enuff_zed]

Carfax says the brake pads and sensors were just replaced last month. Do you think it wasn't installed properly? Or is there something that I need to reset?

Good work so far.
If the brake wear sensor has activated then it’s saying you need new pads. Once it’s been activated you need to fit a new one.

There are two wear sensors, front left and rear right. They push fit into the inner pad and when it wears down they come into contact with the disc, the plastic wears away and they short out. Once this happens you have to fit new sensors.
It is possible that when the pads were replaced they didn't fit the sensor in tightly so it has come out and been caught on the disc.
You will need to check them both out.

[Z4Mariner]

. . . what Enuff-Zed said. If a worn-through sensor was not replaced or if the electrical connector for the sensor is not seated, you will have the light. You should be able to see when you check them.