E89 30iSDrive 2009 -- Parking Brake Inoperative

Varixto

Varixto

Member
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.:
1780844674541.png
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.
 
Previous thread on this here
Varixto

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

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...
 
colb said:
Previous thread on this here
Varixto

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

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...
Click to expand...
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...
 
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...
 
Need to check if the actuators are getting power, test with a multimeter. Also check the fuse for them F52 in the fuse box.
 
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.
 
colb said:
Need to check if the actuators are getting power, test with a multimeter. Also check the fuse for them F52 in the fuse box.
Click to expand...
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).
z4-fusebox.jpg
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?
 
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.
 
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.
 
Matt.rowley.1990 said:
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.
Click to expand...
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.
 
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.
 
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