Hill Start Assist Sensor

[Steve84N]

Hi,

Does anyone know where the sensor is that the hill start assist function uses?

My coupe has thrown a yellow parking brake warning light and the hill start has stopped working. I've currently got the seats unbolted and tilted back but I can't see it...

Any help appreciated.

Thanks

Steve

 

[Smartbear]

Doesn't it use a sensor on the hub that counts a toothed wheel? I thought it piggybacked an ABS sensor but I could be wrong :?
Rob

 

[Steve84N]

It couldn't use an ABS sensor on the toothed wheel as it knows you're on an incline when you're not moving. I believe it's something more like an accelerometer.

My code is 5E34 and the text said electrical fault or signal out of range. I read somewhere there was a sensor under the seat but that may be just on the e46. I need to find it to see if the connection is bad or the sensor is dead. It happened on holiday and there was stuff getting lost under the seat that may have dislodged a connection if it is there.

 

[Scooba_Steve]

Does it not use the same tilt sensor as the alarm? That should be in the cubby behind the drivers seat.

 

[Steve84N]

I have no idea, would I have to dismantle the the centre console etc to get the trim off to see?

 

[Scooba_Steve]

No the tilt sensor is just behind the cubby/sub, that's only clipped in. One way I can think of testing it would be to lock and arm the alarm then jack the car and see if the alarm goes off.
I can't imagine there would be another level sensor anywhere. Your problem could be completely unrelated to angle of course, defo not just a brake pad warning? I don't know if that would disable the assist.

 

[Steve84N]

Good tip about the tilt alarm, I'll try that tomorrow.

I've visually checked the pads and there's plenty left after I replaced them last year.

 

[Scooba_Steve]

Weird, tried a battery disconnect? Aside from testing the tilt, check and clean the connection I cant think of anything else.

Good luck with it.

 

[Steve84N]

Will try the battery disconnect too just in case it clears the fault as INPA didn't.

 

[Steve84N]

So it turns out the tilt alarm works just fine so it's probably a different sensor...

 

[Steve84N]

I've read of people having this issue on other BMWs and it seems to be the speed sensor cluster located underneath the seat under the carpet. Does anyone know of a Z4 being broken for parts where I could find one of these second hand?

Looks like this:



Part No: 34526769174

Thanks

 

[Steve84N]

If anyone finds this thread with the same problem it was the speed sensor cluster. BMW want around £430 for a new one...so I held out and got one from a Z4 being broken for £55.

It's not too hard to replace, just need to take the seat out and lift up the forward section of carpet to swap it out.

 

[Scooba_Steve]

Really useful to know, couldn't find any documentation about it anywhere.

 

[craig3.2]

Good find,and helpful info on he fix

 

[Steve84N]

I found the answer through reading about the same problem on e46 cars. It's handy that the Z4 shares parts and design.

 

[Scooba_Steve]

And all the same flaws! :lol:

 

[dman057]

I've got the same issue on my E85 - error 5E34, so I think I'll try and get hold of a sensor and replace it. Which seat is it under please?

 

[TOM4S]

If anyone finds this thread with the same problem it was the speed sensor cluster. BMW want around £430 for a new one...so I held out and got one from a Z4 being broken for £55.

It's not too hard to replace, just need to take the seat out and lift up the forward section of carpet to swap it out.

Thanks for posting this. Not a lot of info about. Was this under the driver or passenger seat (UK)?

Tom

 

[Steve84N]

From memory it was the driver's side on the right.