Power Steering failure

[k31ron]

My power steering has stopped working and the EPS light is on the dash, Ive searched and read a variety of post's but wonder if anyone knows a way of ruling in or out the complete EPS assembly as it costs about £2.5K to replace!!

I saw a thread from domsz4 and have similar symptoms but sadly I don't have the same issue the connector is well in place.
All fuses are fine (including 22) and ive tried a full battery reset all to no avail.

I tried INPA to find a code but it says the EPS module is not accessible so can't read it (which I'm guessing isn't normal)

greatly appreciate any thoughts or suggestions on this as I really don't want to start down the road of horrific repair bills which will quickly cost more then the car is worth.

 

[Toe-side]

Any codes from steering angle sensor?
I am researching my steering problems and the codes appear on the ABS section of my C110 reader for some reason

 

[k31ron]

Any codes from steering angle sensor?
I am researching my steering problems and the codes appear on the ABS section of my C110 reader for some reason

The only Error code im getting from the whole car is

Variant KOMBI85
Error Registration 1 : 0x00FA: no CAN ID EPS1
Error accurances: 110
Open Circuit
Error present
Error Code: FA 44 6E

And I haven't been able to work out what that means I was wondering if EPS1 relates to Electric power steering, but I think KOMBI85 is the instrument binacle.

 

[Toe-side]

That error code isn't throwing anything up. Is that a code from your reader being unable to communicate with the car? Doesn't look like the normal code format.
Have you thought about taking the car to an "Independent" to read the codes?
Are you able to drive it with no power steering??

 

[domsz4]

The car should be fine to drive just heavy. At the end of the day the system is not hydraulic so good old fashioned rack and pinion. Essentially there is a torque sensor and steering angle sensor and motor that provide the servo assistance.

For me Kieron it was simply the motor power that had come loose. It stopped working as I went over a bump. Take the cowl off and find the connector with the 2 thick wires and mike sure it is on right and making connection. I guess you could also put a meter across it and see if your getting anything.
You said you've already checked this so next step would be a diagnostic. I read that the either of the two sensors could go and the whole system will fail. I can't remember exactly but you said your found my post before. For sure the sport button was out.

I found out you could replace any of the bits but the easiest thing would be to just buy a column from eBay and fit the whole thing. I think you might need some coding doing tho

 

[k31ron]

That error code isn't throwing anything up. Is that a code from your reader being unable to communicate with the car? Doesn't look like the normal code format.
Have you thought about taking the car to an "Independent" to read the codes?
Are you able to drive it with no power steering??

It's an INPA diagnostic, Indy had a quick try and couldn't get anything more and said to book in for a time consuming attempt to trace issue.

Yes you can drive it's actually preferable to having EPS at speed but parking is very hard work.

 

[k31ron]

The car should be fine to drive just heavy. At the end of the day the system is not hydraulic so good old fashioned rack and pinion. Essentially there is a torque sensor and steering angle sensor and motor that provide the servo assistance.

For me Kieron it was simply the motor power that had come loose. It stopped working as I went over a bump. Take the cowl off and find the connector with the 2 thick wires and mike sure it is on right and making connection. I guess you could also put a meter across it and see if your getting anything.
You said you've already checked this so next step would be a diagnostic. I read that the either of the two sensors could go and the whole system will fail. I can't remember exactly but you said your found my post before. For sure the sport button was out.

I found out you could replace any of the bits but the easiest thing would be to just buy a column from eBay and fit the whole thing. I think you might need some coding doing tho

Thanks I might try and locate a wiring diagram an check all connections with a multimeter

 

[Daniel411]

Hello all,

I experienced a total power steering failure yesterday in my '06 Z4 3.0i while driving on the highway - no EPS light warning before or after, nothing. I was driving along at highway speeds on a straight highway and briefly smelled a faint electrical burning smell that then went away so I thought it maybe came from outside. About 45 minutes later I pulled off the road to put gas in when I noticed the steering feels very heavy - almost missed the curve in the offramp because it took me by surprise. When I left the gas station it was obvious all power steering was gone, but was able to continue driving it - it's ok at highway speeds.

Anyway, researched this and found out about the electric power steering and possible need to replace the entire column and servo which cost at least $2.3k which is totally nuts! It's very likely the servo has fried, but apparently even though it's a simple electric motor that can be found for a couple of hundred bucks, it can't easily (or at all) be replaced on its own - the entire column plus servo must be replaced and programmed. I brought the car to my BMW mechanic who is pretty knowledgable and even he doesn't know how to quite deal with this and is looking into it.

@k31ron: How did you end up fixing the problem, did you have to change the whole column or were you able to fix it another way? Does anybody know if the servo motor can be changed independently?

All these electric computer controlled parts suck - I've had more problems with my Z4 than any previous beamer I've owned. Electric water pump went out it was $1500, now this goes out, it might be $3000+ with parts and labor. Things that used to cost a few hundred bucks to fix now cost 1000s!

If anyone has further insights or advice, I'd really appreciate it!

Thanks in advance!

 

[Daniel411]

Power steering failure solved and thought I'd share my experiences with the forum - it may save someone some serious bucks!

My mechanic spent several hours looking for codes and trying to diagnose the problem and could find nothing. There were no codes, no warning lights, no burned fuses, no bad wires, nothing, yet the EPS was dead in the water. After consulting with several other mechanics he concluded the EPS unit is likely fried and needs replacement, but said he couldn't do it himself as it's too specialized a job and he doesn't have the right programming tools. So he sent me to another nearby BMW mechanic who he said had done this before and is familiar with the problem and has the tools for the job. Total replacement cost quote: $3,800!! The part alone is $2,300 to $2,700 I looked it up online myself, and he said the other guy will not work with used or rebuild EPS columns because they always cause problems. I almost cried.

As I'm about to pull out of the lot to go to the other mechanic, the car wouldn't start so the guy gives me a jump with a portable charger. And lo and behold the power steering comes back on!! Neither of us could believe it, especially he who just spent a few hours trying to diagnose the issue.

What we concluded is that the EPS unit was not getting enough juice from a weak and dying battery, causing it to malfunction and shut itself off at startup. The battery had been weak for a while and was barely starting the engine and I knew I had to change it, but I hadn't gotten around to it.

So if you get power steering failure, before throwing a bunch of money at the problem, make sure you check the fuses (esp 22), the wires and the battery. A weak battery can apparently cause the EPS to malfunction even if it can start the car. I changed the battery and no problems so far, hopefully this won't come back.

Hope this saves somebody from a nasty expense...

 

[Grumpyowl]

Great conclusion for you there Daniel411
I'm sure this will be great information for anyone having similar problems now or in the future.
Enjoy your car

 

[Toe-side]

Thanks for the update and great news that it was such a simple issue.

 

[skelters]

I had the power steering fail on the 2.5 SE I had.

Turned out it was the Air Conditioning unit that had just been replaced had a software conflict with the power steering unit.

Dealer re-flashed the firmware to an older version and everything worked.

This was over 6 years ago and the part was £1700 + vat + fitting.

They had never seen the control unit fail before and didn't know how long it would take to replace.

 

[justmatt]

Thanks again guys, had the same issue and tuned out the connector had worked itself loose, 5min fix awsome!!!!

 

[konrad1511]

hi Justmatt,

does the 2008 Z4 4 Cylinder "Sport" have this connector ? And where is it located ?
My power steering works but a few lights on dashboard on like traction control etc and car pulls to the right.
Sometimes at very low speeds like up to 15mph those dash lights are off but come on again when speed increases....

Many thanks in advance....