[OmarBMWG30]

Hi everyone,
I’m stuck with 60 different fault codes on my 2018 BMW G30 540i
Car was ok in the morning
Then at noon time it gave me all these codes at ones
There was few codes I already knew about like the AC flap motor, a code for the moonroof, a code for camera due weather conditions and a code for tire pressure sensors low battery
It looks like there is an electrical issue but I’m stuck and I don’t know where to start
Many systems got disable after I got these codes
Airbags disabled
Steering wheel feels heavy only above 7mph, below 7mph steering is ok, this is very strange behavior. I already checked steering fluid and it looks clean
Check engine light on
DSC light on
Wrench light in middle of instrument cluster
Brake auto hold disabled
360 camera disabled, when I put the car into reverse the backup camera doesn’t come on automatically, I have to press the button to make it work, also the 360 camera doesn’t work at all even when I press the button
Active cruise control disabled
Active blanket assist disabled
Blind spot disabled
Front and rear Sensors disabled
Auto high BM disabled
Seatbelt tensioner disabled
Adoptive front headlight stopped turning with steering wheel
The Warnings I have on the screen are:
Restaurant system, seat belts, airbags
Drivetrain
Chassis stabilization
Reduce driver assistant

If anyone had this issue or can help me that will be very appreciated. I have Autel MaxiCOM MK808BT Pro and bimmerlink scanner so if you want me to check something specific in the car I can do that

Engine feels like it is running good with no miss fire or rough running, no codes for miss fire
Transmission feels ok while changing gears
Breaks feels ok, not sure if ABS still works but there is no ABS light on the dash
Steering is heavy above about 7mph

Here are the codes I have

[adhrp]

Perhaps the battery? How old is it? A dying battery can cause all sorts of codes to pop up at once.

[lnxguy]

Battery is the first thing you should look at. Definitely after seeing all of these.

[OmarBMWG30]

I already replaced the battery with a new OEM battery. Got the same battery from bmw dealer
The issue and all the codes still there even after replacing and registering the new battery. I tried to clear the codes, some of them get cleared (the ones for check engine light because the check engine light goes away for few miles and then comes back) but the codes for airbags, safety systems, DSC, and the wrench light all stay and not able to be cleared
By the way, I bought the car in 2018 new, and I keep it since then. No accidents or any major problem. I did an oil change at the dealership last month and they did not flag anything not even the battery

[Joe-BMW33]

Originally Posted by OmarBMWG30

I already replaced the battery with a new OEM battery. Got the same battery from bmw dealer
The issue and all the codes still there even after replacing and registering the new battery. I tried to clear the codes, some of them get cleared (the ones for check engine light because the check engine light goes away for few miles and then comes back) but the codes for airbags, safety systems, DSC, and the wrench light all stay and not able to be cleared
By the way, I bought the car in 2018 new, and I keep it since then. No accidents or any major problem. I did an oil change at the dealership last month and they did not flag anything not even the battery

I take it you replaced the battery itself and not the dealer or indie? What are you using to clear codes and register the new battery?

These types of multiple, random and all over the place codes always lead to power issues. Even a slight variance in required voltage will light up your dash like a christmas tree. I can't remember if the 540 has a second battery like the M550, if so, could be that one, if not, I would move to the alternator.

[OmarBMWG30]

I replaced the battery myself.
I used this tool Autel MaxiCOM MK808BT Pro to register the new battery and clear the codes, this tool has bmw configuration in it
I didn’t find another battery in the car so I’m guessing it is only one battery?
The battery is in the trunk in the middle where the spare tire goes if there is one
If there is a 2nd battery where should I find it?

[Joe-BMW33]

Originally Posted by OmarBMWG30

I replaced the battery myself.
I used this tool Autel MaxiCOM MK808BT Pro to register the new battery and clear the codes, this tool has bmw configuration in it
I didn’t find another battery in the car so I’m guessing it is only one battery?
The battery is in the trunk in the middle where the spare tire goes if there is one
If there is a 2nd battery where should I find it?

The auxiliary battery is in the engine compartment on my M550.

[Joe-BMW33]

https://g30.bimmerpost.com/forums/sh....php?t=1464028

Back left passenger side near the firewall under the cover in the corner.

[OmarBMWG30]

I checked and it looks like the car doesn’t have an auxiliary battery. When I left the cover in the engine compartment passenger side I don’t see any battery there (see pictures)
I looked on google and it seems that some of the 540i has auxiliary battery which is located under that cover in the engine compartment and some of them doesn’t have that battery like my car

[Joe-BMW33]

Originally Posted by OmarBMWG30

I checked and it looks like the car doesn’t have an auxiliary battery. When I left the cover in the engine compartment passenger side I don’t see any battery there (see pictures)
I looked on google and it seems that some of the 540i has auxiliary battery which is located under that cover in the engine compartment and some of them doesn’t have that battery like my car

Yeah, I would now move to the alternator and have that tested.

[capese21]

Aux battery is on the inside right of the trunk behind the trim panel near the fuse board.

7 series but same location.

https://www.youtube.com/shorts/vxJWy...?feature=share

[OmarBMWG30]

I don’t think my car has an aux battery. Both sides of the trunk is just empty and has storage compartment. When I open the fuse box I can’t see any battery there too

[DrVenture]

If you have a voltmeter, you might check the voltage across the battery while running/idling. A typical reading is around 13.5 - 14.5v on most cars.

And around 12.5 - 13.5v on a fully charged battery not running.

If the battery and alternator are testing okay, it might be that a rodent chewed through something or you have a faulty ground. If I were looking into it myself, I would pick a system that has a permanent fault and see what is happening with a basic voltmeter check. Or with the Autel signal functionality, as needed. Preferable a system whose module and harness are relatively easy to access. Then start by checking the fuse feeding that circuit. Move on to the actual faulted module and check GRD, voltage and (assuming CANBUS) the digital signal with the AUTEL oscilloscope function or an actual O-scope.

Some times a CANBUS goes open too, corrupting everything on that CANBUS branch. Each branch, usually two, would have a 120 ohm resistor located at the last module on each branch. If checked at the origin point (power disconnected at battery) you might read 60 ohms on a good system since two 120 ohm resistors, in parallel, is 60 ohms. I am not sure how many CANBUS branches that a BMW has. But, if they use CANBUS it should be a universal specification.

And I would look at schematics to see what all the impacted systems have in common (if anything), like a relay that should be delivering power to the impacted systems.

[OmarBMWG30]

DrVenture
Do you know a website or a place that I can get schematics from?

[OmarBMWG30]

DrVenture
So I did check voltage by connecting voltmeter to battery
See pictures for voltage

[OmarBMWG30]

Is there a way I can connect the voltmeter to the alternator directly? So I can see the voltage that is coming out if the alternator?

[DrVenture]

What you see at the battery is the alternator output, for the most part. If your are willing to download a large file and install it on a Windows machine, you can install ISTA which I believe has all sorts of info such as wiring diagrams.

I sent you a PM.

The running voltages seem a tiny bit low, but might be normal for your car. Should be okay, I think.

[OmarBMWG30]

DrVenture
Thank you very much for the help
I’ll download the software and hopefully I can find something

[OmarBMWG30]

DrVenture
So I installed ISTA + which includes ISTA D and ISTA P but I only have the enet to obd cable
First scan gave me 71 codes, I cleared the codes and now there are 31 codes which I was not able to clear at all, I tried to clear them 3 times and they weren’t cleared
These codes are for safety systems, airbags, 360 camera, seat belts tensioners, ACC, lane keep assist, blind spots, front and back sensors, and there are other computer codes too, I’ll take a picture of the fault tree and post it soon
Also there is a steering angle sensor code too, maybe that is the issue because since this problem happened the steering feels heavy but the strange thing is it feels way lighter than before only below 6mph and then it goes heavy
I went to 2 shops, one of then just a regular shop for all cars and they said they don’t know what is wrong
The other is a bmw specific shop and they guy said he doesn’t know what is going on but he said I can leave the car and he can do a deep dive Diagnostic but he wanted to charge me $300 for that diagnostic which is $50 less than the dealer, I’ll probably take it to the dealer and get the diagnostic their. I feel like these other shops will keep guessing and I’ll keep spending money and changing stuff around the car multiple times before getting to the end of this issue
When I was checking the car on ISTA the program kept telling me voltage is under 12.55v
I charged the battery and this Warning Disappeared but it came back later
After I charged the battery the voltage looks better, 12.9v engine off and 13.9v with engine on, ac on, lights on

[DrVenture]

Those voltages are more in line with my expectations. Electronic diagnostics are tricky and can be time-consuming. Not all shops or mechanics are good at it. A flat rate for diagnosis is not a bad deal. If your battery is good and you nave codes that will not clear, I am suspecting something on the Canbus, but that is a SWAG.

All the codes that you list seem to be related to safety and drivers assist (airbags, sensors, cameras). Unplugging the steering angle sensor might help to clear all the other codes. Maybe.

I will say that my son had a rodent chew through a 4-wire steering rack harness a few years back (Honda), and all sorts of warnings seemingly unrelated to steering came up on the dash. if you have a lift, you could get under there and remove the belly pans and look for signs of corrosion or rodent activity around the harness going to the steering rack. Or on a set of ramps, even.

[OmarBMWG30]

So I got the car back from the dealer today. They fixed it!
It was a software issue, some how the car computer software went down, I don’t know how this happened, and the dealer doesn’t know how it happened. They had to reprogram the whole car again.
There wasn’t any hardware issue which is good
But I still don’t know how the software gave up like this
Initially they said $500 to diagnose the car but if the technician started to take off parts to find the problem then it will be $250/hr in addition to the $500 diagnostic
I think I was lucky that it was a software only and the fix was already included in the $500 diagnostics fee

[DrVenture]

Glad you got it fixed. It is strange if multiple modules lost programming. Or that any module lost programming without any real hardware faults present. Thanks for the update.