I've got a 2007 MCS Convertible that the PDC stops working. When I looked into it I find that the 5 amp fuse has blown. I've gone through a number of fuses and after I replace it, the PDC works for a couple of days and then the fuse blows again.

Does anyone know why?

 

The PDC uses the same fuse as the Power Steering pump fan. I would check the fan to see if there is anything obstructing the fan blade. Spin the blade by hand to test.

You don't want to drive the car for long without the PS fan...

Ken

 

Hmmm....I thought the fan was fuse#39?
The PDC is #40

Have I read that wrong?

 

I show F41 as the fuse for PDC and PS fan.

This was the case on my 05 MCc - PDC stopped working and discovered the PS fan was disabled as well. Replacing the fuse F41 cured both issues.

My ps fan was jammed by debris - simply turning by hand and clearing the debris solved the problem.

Ken

edit: Bentley also indicates F39 as the alternator and PS pump.

 

I checked the fuse door and in my 2007 R52 it is F40. It just shows an "icon" of the PDC next to it.
I also got up under the car and there is no debris or damage to the fan--so I'm still stumped!
Does the fan run all the time? If it does I can have the car running and check the fan to see if it is running.
Does the fuse blowing show up on an ODB reader? I can check that as well.

 

I checked my ps fan by removing it from the car and connecting it directly to the battery - this will tell you if the fan is working properly (keep your fingers away from the blade!).

You can also listen for 'rattling' noises - I had the bearings in the ps fan go out and it made a racket when it ran...

I did not have any error lights or codes when my fuse blew...

My only other suggestion is to take a look at the wiring behind the rear bumper cap - you will be able to see it from underneath - look for any abrasion in the wiring against the bumper structure that may be causing an intermittent short... (edit: that would be the wiring for the PDC sensors.)

Let us know what you find...

 

Here's what I found- you're right- the PDC and the fan are on the same fuse- in my R52 it is #40. I snapped the cover grill off the fan and it had just enough road dirt to be slightly hard to turn. I spun it a few times to work out the grit- problem fixed!
The fan does work off some sort of thermostat- it cycled while I was under the car. If I didn't have the PDC set up to beep once when I put the car in reverse I'd have to get close to something and not have it beep to find out I had a problem- there are no error codes, warning lights, etc. Of course I'd have found the problem when the power steering pump overheated and needed to be replaced (maybe). I can certainly see investing in a different "grill" that allowed air flow but not so open that all the grime got up there.
Thanks for your help.

 

Glad you found the problem!

Cheers,
Ken

 

Thanks for the information in this thread, this seems to be a common problem.


We just got a used '08 R52 Convertible, and I noticed the sensors in the bumper during the process.

There was no PDC function in the cabin though, so I figured maybe BMW just put sensor plates/covers in all bumpers even if they don't have PDC equipped.

But no, I checked my fuse box and found F40 blown.

Replaced it today and we will see how long it lasts. I will be sure to check the power steering fan if the fuse blows again.

 

Anyone that is having issues with their PS Fan/PDC fuse blowing needs to take a water hose and wash their PS fan. If it continues to blow, I would take a close look at the PS fan before you're having to replace a pump.

 

I drove up on ramps to take a look at the PS fan.

There doesn't seem to be any buildup, there is clearance between all the blades and the shroud.





But, I cannot turn the fan by hand.

The above comments make me feel like the fan should spin freely.

Also, this video suggests that if the AC is on with engine running then the PS fan should also be spinning
I started car and turned AC on, but the PS fan did not spin. Fuse is still good and PDC is working.

I assume this means my fan is dead, but am not sure about other ways to check function. I wonder what the service manual says about this.

Here is a Tech article from Pelican for fan replacement

 

You need a new fan. I bet if you unplug the fan you will quit blowing fuses. The fan does need to spin freely. You can remove the fan and try to clean it but I'm afraid the damage is already done. You don't want to risk a $350+ Power steering pump for a $100 fan.