[macmaverickk]

I have done hours of research and I'm afraid I'm coming up on a dead end. Hopefully this can be resolved because my next step is bringing my car in.


SYMPTOMS:
I was cruising my 335i (AT) at about 75mph last month when suddenly the RPMs jump to 6k and then down to 1k, the transmission slips, and a myriad of warnings display on the iDrive (Engine malfunction, Transmission malfunction, DCT malfunction, etc). I pulled over and tried to restart the car - same warnings show plus a Start-off Assistance warning. The car was drivable, however at a max speed of about 40mph because it seemed like the car was stuck in 3rd gear or something. I limped all the way home. Also, a side note... my car had idling issues and long-ish crank times a good 6 months before this all happened. By "idle" I mean the car would feel like it would stall after starting if i didn't give it a little gas while warming up... and if I threw it in reverse without a little warm up, the car would stall. Happened 90% of the time on cold start-ups.


DIAGNOSING:
My trusty K+DCAN showed only 3 faults recorded in the system, and one of them was a shadow. 2B3D (Combustion misfire), 2A94 (Crankshaft Sensor), and 3100 (Boost loss - the shadow code). FYI... These were fresh codes.


RESEARCH & SERVICING:
I read multiple sources that symptoms of faulty/old VANOS solenoids mirrored everything I was experiencing. So that was the first thing I took care of. I purchased two, brand new BMW solenoids and installed them. No luck. Refreshed the codes again, but this time 2B3D was gone. UPDATE: 2B3D came back (With no symptoms)

I researched 2A94 more, and found a handful of people who experienced the same break-down I had... they all replaced the crankshaft sensor and all their problems went away. So I picked up a sensor from the nearby dealership, installed it that night, and still no luck. The car didn't even act as if I did anything this time. Same symptoms, same two faults (2A94 & 3100).

Discouraged, and out $400, I got back to researching. This time I found a couple guys with the 2A94 fault code only 'cause there was no power going to the crankshaft sensor. Their fix was simply replacing a blown fuse, and their entire service bill was all of a couple bucks. Well again, not the case for me. I pulled EVERY SINGLE FUSE and did an ohm test with a multimeter - all of them working fine.




Any ideas would be greatly appreciated... this is killing me... my bimmer has been out of commission for way too long. Thanks

[GMWNashville]

So have you checked for voltage to the sensor?

[macmaverickk]

I decided to book the car into my mechanic... I'm going to have very little time to be working on my car these next few weeks anyway. I'll update with the diagnosis hopefully by the end of the week.

[macmaverickk]

Well don't I feel stupid... The new sensor wasn't inserted fully. The mech fixed it and cleaned up the oil mess it made. I even double checked the sensor before putting the car back together. That was a nice, $300 lesson.

[elmoose]

chasejennings Sorry to Hear that. The Same exact thing just happen to my car i ordered the Crankshaft Senor today and will get it next week..Lets see what happends

[macmaverickk]

Good luck... THIS helped me quite a bit in locating the sensor. His DIY says to unplug the sensor before unscrewing it and replacing... However I found that it's much easier to first unscrew the sensor (Have a magnet ready cause it's easy to drop that bolt), then pull from the base of the sensor to pop it out. THEN it's much easier to unclip the sensor from the cord and replace with the new one.

Also fun fact: 2B3D came back today. No symptoms with the car... Just an illuminated SES on the dash. I've been looking high and low online and can't find anything at all. Anyone have any insight? It's the only DME code showing.

[macmaverickk]

2 years later.....

Thanks uberhonky for reminding me to finish this thread!

I finally concluded that 2B3D was related to the fuel delivery system because I replaced the HPFP and it resolved a lot of my issues, including the 2B3D code entirely. I then later replaced half of my injectors and things got even better (idle and acceleration were revived). About a year down the road my fuel sending unit (right under the rear seat cushion) began leaking. When I finally got all that tubing replaced, my car's first start took a solid 5 seconds to crank, and as a result 2AAF and 2B3D tripped in my DME (This is when I realized 2B3D was definitely a fuel-related code). But after clearing those and driving a bit, everything ran very smoothly thereon.

Another thing I did that greatly helped in the overall performance of my car was walnut blasting my intake valves. I did it at 153K miles... probably should've been done at 100K at the latest. I did it myself using bavauto's carbon cleanup kit. It required a little tinkering, but all-in-all I noticed the biggest change in my car's throttle response and torque than any other job I've done on my car.

[hybrid90]

Sorry guys, but this is the best direct answer I have found for this, but I have a symptom that may or may not be directly related and make a difference in the diagnosis.

Just like the OP, I was driving around 75 w/Cruise Control when suddenly the car kicks itself out of gear into neutral and I get all of the warning lights. I didn't have my scanner with me (stupid! stupid! stupid!) so I had to have the car towed to the nearest town. The next morning, I came back with my BimmerGeeks ProTool and scanned it, getting the 2A94 and 3100 codes. I also got a CF3E code which says "signal from engine management: speed, engine" and a 5E1A which says "engine management interface".

Here is where it gets interesting and possibly changes the diagnosis: A week ago, I had an oil change done and while it was there, they claimed that there was a recall on my injectors (this was weird because I knew about the ones for the 2008 build N54's but I have a 2013 335is. They claimed that they didn't need to swap them out because I already had the "index 12's" but that they had to go in and "look" at them. I"ve had issues with them doing a regular service and forgetting to tighten something or not clip something back in completely. This is relevant because after I scanned it, I went ahead and reset the codes to see what would happen. After that it drove absolutely fine after an 8 mile test drive. so I drove it home (30 miles). Again, cruise control set at 75 and right when I get to town, it kicks the car into neutral again and all of the warning lights pop up.

Again, I pull into a parking lot (luckily I was just coming up on an exit and was able to coast right into a parking lot) and before I turn the car off, I reconnect my BimmerGeeks ProTool, scan the car again and get the exit same codes again. So again, I turn the car off, reset the codes and when I restart, it's fine again and I drive it the rest of the way home (another 5 miles through town). Once there, I turn the car off and now it's just sitting.

The fact that it's intermittent tells me that something is loose, but since I don't understand what and where the sensors really are, it's hard for me to say. So I don't know if the Crankshaft Sensor is something they would even touch when "visually inspecting" the Injectors or not.

Any help or ideas on this would be greatly appreciated. I can follow directions and am mechanically inclined, but this is well beyond my scope of knowledge.

[Aode06]

All these issues above come from a large failing ground strap behind the engine .
It's usually crusty green.
This causes I crankshaft codes,injector codes,fuel codes,boost codes.
Because they all need that ground.

[Aode06]

Also the positive cable from the trunk including through body connectors have failed on most n54s. Run a O guage amp wire from the positive battery under carpet to the engine compartment terminal ,don't bother doing it the $3,000 bmw way.
Every single N54 I've seen older than 5 years needs this done unfortunately