Sudden hard to start

R

Raymcm

Member
Z4 e89 20i
It hasn't been out much recently and today I went about 10 miles no issues but after sitting for around 40 mins in and unusually it took 5-6 seconds of cranking. Drive off and soon the brake warning (p) and traction control warnings came on

I drove home and it cut out once in the way but restart after the same 5-6 seconds.

I left it in the driveway and tried it later and still same. Now the eml is coming on and the only code is p0335 crank position sensor (but it's a crappy ebay bluetooth dongle) It could be it or maybe just throwing that up as the cranking is too long.

There's half a tank of fuel been in it since early December.

Question is, what is the relationship between the brake and traction control and hard starting ?

Anything I should try before starting to take it apart to find the CP sensor ?
 
Next question .. where is it ?

What I assumed to be the crank sensor on the 13627595860 listed as official bmw part ??
 
If its set a code for crankshaft sensor then go with that and replace. As an aside when I renewed my CCV system on my E85 I didn't plug my camshaft sensor back in and when I started the engine it turned over a few times before it fired up, realised I had left the sensor unplugged so put it back on which restored the instant starting back to normal. Could be the same symptom with the crank sensor failing.
Parts diagram here Item No 9
https://www.realoem.com/bmw/enUS/showparts?id=LL32-EUR-06-2012-E89-BMW-Z4_20i&diagId=11_4760
 
Thanks

Things are becoming more obvious

It starts fine from cold and runs for about 10-15 mins before throwyup the code which makes more confident that's the problem rather than a knock on from something else like battery issues

I've ordered a genuine sensor from BMW as it's too much work to fit it to risk some cheap clone.
 
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