E89 30iSDrive 2009 -- Parking Brake Inoperative

[Varixto]

As I had not used the car for a couple of weeks I decided to take it for a spin today. I got greeted by the dreaded parking brake yellow warning light on the dash.
I scanned for errors and got loads. I suspected low battery votage and indeed, it was only 12.1V.
(note: I noticed that I had left the lights switch on but it should not matter, should it?)
The car's parking brake button was not lighting and seemed inoperative but I managed somehow to relase the rear brakes upon starting the engine (I heard the motor operating).
I took the car for a couple of long spins and now the battery is on a healthier 12.6V.
I scanned the car and most of the weird error codes were gone. However these three keep coming back.:

The battery is a Bosch one, a bit over a year or so old. The left side (nearside) PB actuator had been replaced with a BMW part a few months ago. I checked in the boot for signs of water ingress and could not see anything wrong.
I would be very grateful if anyone could give me any pointers towards what the problem might be.

 

[colb]

Previous thread on this here

Thread 'Parking brake not working. Yellow warning on dash.'

Aug 31, 2025

And another headache...
This morning I went to the car and got the yellow parking brake warning on the dash. The light on the switch in the centre console is not lit. The parking brake is engaged so I can't drive the car. I plugged my OBD reader and got the following codes:
604A Parking brake servomotor left: Power supply
6581 Parking brake status unequal
Could anyone give me any pointers regarding what could be causing the issue? The parking brake module was replaced after having some water damage a few months ago... I have read online something about a software update for the module but...

• Varixto
• Replies: 13
• Forum: E89 problems

 

[Varixto]

Previous thread on this here

Thread 'Parking brake not working. Yellow warning on dash.'

Aug 31, 2025

And another headache...
This morning I went to the car and got the yellow parking brake warning on the dash. The light on the switch in the centre console is not lit. The parking brake is engaged so I can't drive the car. I plugged my OBD reader and got the following codes:
604A Parking brake servomotor left: Power supply
6581 Parking brake status unequal
Could anyone give me any pointers regarding what could be causing the issue? The parking brake module was replaced after having some water damage a few months ago... I have read online something about a software update for the module but...

• Varixto
• Replies: 13
• Forum: E89 problems

Do you think it's the same issue but on the other side? (ie: the driver's side) It's the first thing I thought but I am getting fault codes for both sides...

 

[Varixto]

The OEM part number for the actuator is: 34216794618
I believe TRW manufactures the OEM part. In Autodoc, a TRW actuator is £81.49 + postage.
However, before I buy anything, it would be great to test if indeed the actuator motor has stopped working and be 100% that it's just that and not something else...

 

[colb]

Need to check if the actuators are getting power, test with a multimeter. Also check the fuse for them F52 in the fuse box.

 

[flybobbie]

My Foxwell reader shows the number of cycles each actuator performs.
On mine it was unequal until one failed with a volt problem.
Then the whole lot refused to work.
Water corrosion inside one actuator.
Replaced with £30 ones off ebay.
I greased them before fitting to keep the damp out.
No problems some 3-4 years on.
Should say replaced as a pair.

 

[Varixto]

Need to check if the actuators are getting power, test with a multimeter. Also check the fuse for them F52 in the fuse box.

I haven't had a chance to have a look at the fuse. Just to double check before I do: it's #52 in the diagram in the photo, right? (ie: in the fuse box by the glove compartment).

This time around the issue is different to when I had it the first time (ie: previous post). This time the button / switch in the central console does not show any light (when I press it, nothing happens), whereas in the previous issue the switch light would be constantly on. Does this point more towards a blown fuse? If so, do you have any pointers as to what could have triggered it?

 

[Varixto]

Managed to get another picture of the fuse box guide, with amperage for each fuse (just in case it helps anyone with a similar issue).

 

[colb]

The absence of the lamp in the switch would point to no power in that circuit, as to fuse if its blown probably due to a short in one of the actuators. Find the fuse and check it, if its blown replace with new one see if it blows again then find the failed actuator.

 

[Matt.rowley.1990]

I haven’t heard of it recently but know that there have been several occurrences of the the software corrupting in the electronic parking break module. This sounds like it could be the case.

 

[Varixto]

I haven’t heard of it recently but know that there have been several occurrences of the the software corrupting in the electronic parking break module. This sounds like it could be the case.

Thanks for the reply and suggestion. I have also read about it but I believe that when that happens it tends to throw a persistent 6017 error as well. I will try the easier checks first (fuse, etc...) and if that doesn't work, I will take it to a local BMW specialist.

 

[flybobbie]

My colleague got rid of her Z4 when the parking brake failed. Last straw of several problems long before we knew how to fix things like roof problems.
Brake failure not uncommon.
If it goes back to dealer and they say you pay to reprogramme say no i won't pay.
It's a design fault of a critical item. It shouldn't fail.
Should be reported to vehicle inspectorate.

 

[Varixto]

My colleague got rid of her Z4 when the parking brake failed. Last straw of several problems long before we knew how to fix things like roof problems.
Brake failure not uncommon.
If it goes back to dealer and they say you pay to reprogramme say no i won't pay.
It's a design fault of a critical item. It shouldn't fail.
Should be reported to vehicle inspectorate.

I might have to take it to a local independent BMW. I wasn't too happy with them in a couple of occasions but it's better than the £200+ per hour labour at my local BMW dealership.

 

[Varixto]

The absence of the lamp in the switch would point to no power in that circuit, as to fuse if its blown probably due to a short in one of the actuators. Find the fuse and check it, if its blown replace with new one see if it blows again then find the failed actuator.

Fuse 52 was ok so I think that it's back to the drawing board...

 

[Varixto]

Well, I thought I should post again to bring this post/thread to an end. After giving it a good run yesterday, when I went to the car this morning, I cleared the error codes and noticed the 604B had completely cleared but the 604A remained, thus the yellow warning was still on the dash.

I noticed that the battery voltage was still a bit low (although at much better charge level). I gave the car a good, long run of about an hour and parked the car. The parking brake was still inoperative so I just simply left it in gear...

Well...I went to the car again later in the afternoon, got in and suddenly...no more warning light on the dash and the parking brake is back to normal!!
I had the car already booked in at a local BMW specialist so it seems that the gods of motoring have favoured me this time... (for a change).

I think that it t was probably the low battery triggering all this. From what I have read, these cars' modules are really sensitive to low voltage levels and I am guessing that's what happened in my case.

I have ordered now a NOCO GENIUS 5 Smart Battery Charger, just in case it happens again.

Thanks to everyone who tried to help.

 

[Mr Tidy]

Great to know your handbrake is now working properly.

It really pays to keep the battery well charged on BMWs of this era - I've had all sorts of random warning lights appear on my cars when their batteries weren't at the best.