E90 Possible Steering Lock Fault

[RECr]

I've already posted this in the straight six bearding thread but thought I would post a separate thread.

I got an amber steering wheel warning light with side to side arrows after switching the car off today. The car then would not restart. When putting the key in the slot I got the usual brake and airbag warning light self test, however pressing the start button with the clutch up did not turn on the electrics in the normal manner. I also noticed that I could turn the steering wheel even with the ignition off and the key out, as though the steering lock was permanently disengaged

I read the fault codes with ISTA+, however no codes beyond the usual N53 NOX sensor related issues were showing. I performed the ELV (steering lock reset) with ISTA in any case.

This did not seem to have any effect although there were one or two occasions where I could turn the ignition on and start as normal, however I never heard the steering lock operating, so it doesn't seem like the lock is intermittently working.

The car has <1yr old Bosch battery in it, although I have been doing a fair amount of short journeys lately so I suppose the battery charge could be low enough to trigger gremlins.

Are there any other things I should be checking?

[Jaybmw]

Have you reset the elv counter ? I had to do that with my e60

[RECr]

Yes I did try that, although the CAS module had no fault codes stored. Did you have any fault codes when you reset your ELV?

[Aluminati]

Key battery.

[RECr]

I will give it a go with the spare key. I read on here ages ago that some people have successfully charged keys by tying them to an electric toothbrush charger. I did assume that a dead key battery would lead to no response at all and I thought it triggered its own warning light. Nonetheless I agree with you that it's worth a try.

I'll also be giving the battery a long trickle charge to eliminate that possibility. The old "measure battery voltage with engine running" to test the alternator is charging doesn't work on cars with IBS doesn't it?

[rosejem]

I have never used this company but found this this information which may be of use.

A BMW specialist in Reading called - Grosvenor

BMW’s recognised repair is a replacement steering column and a bill often upwards of £800.

At Grosvenor we have another solution, we can force the vehicle out of this locked state, reset and clear the existing fault and finally update the CAS control unit (the main security module) to the latest BMW software version. All of this for £83.00 + VAT (quite a saving on BMW’s steering column replacement).

[RECr]

Thankyou, I did see that on Google. It is on a trickle charger now and I can now hear the lock operating again when I insert the key, so hopefully the state of the battery had something to do with it.

Re greasing, or replacing the lock with an emulator looks a fiddly but doable job.

[RECr]

Well after being previously solved by charging the battery, the fault returned on the drive home from holiday this week. Fortunately I did manage to restart the car, and when I got home I was able to read the codes in ISTA+. Once again no codes were stored in the CAS, however I reset the ELV counter. Neither this, nor trickle charging the (18 month old) battery had any effect, although it is probably worth checking the battery voltage.

I am thinking of stripping and cleaning the steering lock but I am not convinced that it is faulty because:

1. I have never heard any untoward noises from it.

2. The light that comes on with the fault is not the usual steering lock light but looks like this



I'll also be continuity checking the wires between the CAS and steering lock as it is almost like an open circuit fault. However I would expect this to throw a code

Fingers crossed the CAS is OK!

[RECr]

Today I disconnected the battery in preparation for removing the steering column. I then noticed the steering wheel had locked (it had stuck unlocked). So I reconnected the battery and now everything works perfectly.

The steering lock makes a smooth, quick sound and doesn't sound like it is struggling. As there are no fault codes stored and resetting the ELV counter did not help the problem I am inclined to think the lock is OK. I wasn't looking forward to removing the steering column in any case!

I am not sure what else to check. The fault occurred after a 2 hour drive, and trickle charging the battery made no difference to the fault on this occasion so I don't think it is a low battery. Having said that the battery voltage with the car turned off is 12.3V so room for improvement .

Any thoughts appreciated!

[helix402]

Is it worth a software update on the CAS?

[RECr]

Yes that could be worth a try. I'll have to get a local coder to do that; whilst I'm happy reading faults and registering component I'm not confident with actual coding or flashing modules.