Power steering error light and more

[BertrandZ4]

Hello everyone,

A few months ago, I acquired a 2010 Z4 23i (E89) with 104,000 km on the odometer. Everything worked perfectly until this week...

A few days ago, after a 200 km trip on the freeway, while parking, the “Power steering out of order” light came on and the steering became very hard. I switched the engine off and on again, and the light disappeared.

The next day, I took the car for a 20 km drive. When I arrived to park, the same light reappeared. I restarted the engine an hour later, the light was still on and the steering remained hard during the return journey.

Four days later, I drive about 200 km without the light on and the steering works normally. When I get to my garage, five error messages appear simultaneously:
DBC out of order: drive moderately
RPA: system error
Steering assist faulty
Parking brake fault
Stabilization system failure

I turn off the engine, restart, and all the alerts disappear... Does anyone have any idea what could be going on? I'm a bit lost...

 

[AnubisZed]

You need your fault codes read, without that it'll just be guesses.

 

[BertrandZ4]

Hello,

Thanks for the reply. Here are the error codes I was able to obtain:




Thanks,

 

[B21]

Usually a collection of errors like this are caused by a faulty module dragging the can bus down and creating false arrows elsewhere..

I suspect you’ll need a more powerful tool like ISTA to troubleshoot each module till you find the faulty one..

Or you can disconnect each module in turn and see when most of the codes disappear..

I suspect for most folks this will need a specialist dealer au fait with bmw electronics..

 

[BertrandZ4]

Hello,

Thank you for your feedback, I have taken some readings with BimmerLink:

Photo of battery :


Battery identification :


Voltage reading with contact activated but motor not:


What do you think of the battery? Could it be the source of these problems?

 

[B21]

80% + of all E89 electrical gremlins are caused by a bad battery…there’s no specfic hard n fast way to definitively test the battery..

Rules of thumb are..if you have obscure electrical issues..

Is battery more than 5 years old..replace

Has the battery ever run completely flat..replace

If in doubt ..replace..

70 ah or 80 ah AGM

It may not solve your problem but to an extent diagnosis is by exclusion..