Intermittent no crank, no start problem is driving me crazy.

[flgman1966]

Oh. To clarify, every time I pressed on brake pedal, with key held to start position, I got the same sound as when I turn key.

[oceansize]

This will help you diagnose key vs EWS vs ignition vs starter (assuming your problem is one of these). Time stamped. Shows you how to bypass the EWS such that if you turn the key and it attempts to start (it won't actually start) then you know your ignition switch and starter are fine and the problems lie with the EWS. If it won't turn over then either the ignition switch or starter is bad and since you already replaced the starter that leaves the ignition switch. If your problems are completely random then obviously this is not as much help but perhaps it can help someone else.

https://youtu.be/LUYgSFgc7-c?t=145

[sapote]

I am still tinkering with this. Still intent on checking EWS. Hopefully tomorrow. However, today found that if I hold the key and slowly pump the brake pedal the car will make the same "buzz" sounds. Understand that I use the term " buzz" loosely. Well, after about 6 pumps and buzzes the car turned over and started. This happened to me one before, but on first pump. When I tried again it didn't work on first pump. So I moved on. Today I found it interesting that that sounds emitted every time I pressed on the brake pedal, so I just continued. Eventually a crank, and a start. Gives me some optimism that I am getting close. If this new scenario means anything to anyone I would love to hear from you. Thank you!!!

SMG needs normal SMG oil pressure before it will start / crank. So make sure SMG pump is working.

The EWS needs both brake on and ignition turned to start in order to crank. So if you turned the key Start and didn't step on brake, nothing happened until you step on brake, then it tried to crank (but it failed for some reason and only made a buzz noise). So there is no special behavior about buzzing and pumping brake.

The problem is that the starter didn't get enough current to engage the solenoid to energize the starter motor. The EWS pin1 wire is the one directly power the solenoid and you need to measure this pin voltage when the solenoid is buzzing. If pin1 has much less than 12v during this buzzing moment, then the EWS is bad -- could be a bad internal relay, or bad 12v supply to the EWS. But first thing is measure pin1, then we will go from here.

[flgman1966]

Problem solved. I received 2 keys when purchased the car. 1 key the battery was bad and I never used it, or at least I could not accomplish locking, unlocking etc remotely. I found the live data associated with the EWS through BMW Scanner. I had looked at this before but didn't really understand it. So, pulled out the old key to compare. Some combination of information from this string and YouTube. So, found that the dead key interacts with EWS perfectly, I just can't unlock the car remotely. The "good" key interacts intermittently. Actually found that if I put the key in "backwards" the "good" key interacts. I scrubbed the key with a wire brush and it worked with first try, but then later tried still failed intermittently. Time to look into the key programming and even the battery in the dead key.

Thank you!!!

[sapote]

That key has a bad transponder chip. You could buy the chip on ebay, install and reprogram the "good" key. If you have looked at pin1 on the EWS then it would not have 12v on the pin.

[flgman1966]

Actually bought the replacement battery for the "bad" key. That was a process, but not too difficult. Now "bad" key has a good battery and is now the good key. Will look into the transponder chip though. Thanks!!

[FrumpleD]

Oh boy, I totally understand how an intermittent no crank, no start problem can drive you crazy. It's one of those issues that can really test your patience. Have you tried checking the battery connections? Sometimes a loose or corroded connection can cause these kinds of problems. If that doesn't do the trick, reaching out to a towing company like Towing Company Carrollton GA could be a lifesaver. They're experts in getting vehicles safely transported, so they might be able to help you get your car to a mechanic without any additional stress. Hang in there, my friend!

[Maxima SE]

I had an intermittent no start issue on my E46 M3. It would only happen on very hot days. I went on a spree and changed a bunch of unnecessary stuff. Got a new key, new clutch switch, new starter and the problem seemed to resolve..... but then I bought a Z4M and experienced the same intermittent no start issue on hot days... even with a new starter and battery. So I started reading a ton on the forums and finally found out that the problem with both of my cars was the clutch stop. On super hot days it expands and you can't depress the clutch all the way and it won't let you start the car. If you leave the door open for about 5 minutes or so to cool the interior then it cranks no problem. Or you can just adjust the clutch pedal. So if your issue is limited to hot days then this is most likely what is happening and yes it can drive you CRAZY !

[Wizy]

I am still tinkering with this. Still intent on checking EWS. Hopefully tomorrow. However, today found that if I hold the key and slowly pump the brake pedal the car will make the same "buzz" sounds. Understand that I use the term " buzz" loosely. Well, after about 6 pumps and buzzes the car turned over and started. This happened to me one before, but on first pump. When I tried again it didn't work on first pump. So I moved on. Today I found it interesting that that sounds emitted every time I pressed on the brake pedal, so I just continued. Eventually a crank, and a start. Gives me some optimism that I am getting close. If this new scenario means anything to anyone I would love to hear from you. Thank you!!!

Hello. I have the same problem as you described except for one detail. The problem is much more prevalent when it's hot, but I also have this problem when it's cold. I also have a key that doesn't start the car at all, whereas it used to work. The other key works randomly. Do you have any idea where this could be coming from? I have a 2004 BMW e46 318td.

[bavarian3]

I had an intermittent no start issue on my E46 M3. It would only happen on very hot days. I went on a spree and changed a bunch of unnecessary stuff. Got a new key, new clutch switch, new starter and the problem seemed to resolve..... but then I bought a Z4M and experienced the same intermittent no start issue on hot days... even with a new starter and battery. So I started reading a ton on the forums and finally found out that the problem with both of my cars was the clutch stop. On super hot days it expands and you can't depress the clutch all the way and it won't let you start the car. If you leave the door open for about 5 minutes or so to cool the interior then it cranks no problem. Or you can just adjust the clutch pedal. So if your issue is limited to hot days then this is most likely what is happening and yes it can drive you CRAZY !

Thanks for this tip! hilarious(not really), mine does the same thing and it is always on hot days when the car has been left out in a lot.

[jdamore44]

I had the same issue, No crank condition on Hot days. I adjusted my clutch stop a little in so I could extend the pedal further when pressed. I haven't had a no crank condition since. I believe that was the culprit.