Hi guys I’ve been having some issues with my 2011 128i N51 engine. Bought it and had two codes. 1st one was for the EAC sensor 2AD8 on INPA. The sensor is integrated into the radiator but the party I purchased it from “swapped” the sensor and the code still was there. The ECU ended up needing to be re programmed. Just putting this in here for anyone else dealing with this. However the other code 2A7A doesn’t have much info about it on forums. Engine basically misfires on cold start and autozone free scan defined it as over retarded bank 1. Everywhere I see is Vanos related but I also see others saying the camshaft sensor. The Vanos solenoids on the outside where they sit on engine look dirty such as buildup but I haven’t cleaned them yet. My goal is to take out , clean , reinstall and then clear the code to see if it comes up again. Can anyone give me more insight on why I am receiving this error? Thank you 🙏🏻
UPDATE: Cleaned the Vanos solenoids, which really were not as dirty as i initially thought, reinstalled but the engine still fluctuates rpm's very rough for few seconds on cold start. Purchased VDO camshaft sensor off FCPeuro so i hope this fixes the issue. Let me know if you guys have any info on INPA code 2A7A in case the sensor doesn't fix my concern. Thank you.
UPDATE 2:Still had a horrible cold start rough idle after replacement but seems to be working ok for 50 miles so far. Just still got my guard up as I feel this isn’t the fix. What other information is there on 2A7A!? Thank you
Last edited by TaurusThomas; 06-05-2020 at 04:17 PM.
UPDATE 3: Bought OEM cam shaft sensor but the misfire on cold start/service engine soon still occurred. However, when I was cleaning the Vanos intake solenoid, i noticed a branding on the outside "World Source One". Called all the auto stores (auto zone Oreilly’s etc) in regards to the company and the part. They basically were unaware or of no knowledge of it. I called Kuni BMW and they confirmed this is a aftermarket part as their in house solenoids have BMW stamp. So I have been doing research for the over retarded bank 1 code from my INPA scanner and narrowed it down to this.
Last edited by TaurusThomas; 06-06-2020 at 12:01 AM.
UPDATE 4: so KUNI confirmed both VANOS intake and exhaust were China made aftermarket products. Paying $360 for both new genuine BMW parts. Getting on 6/6/2020 then I will come back and see how cold start acts up.
UPDATE 5: installed the genuine BMW Vanos solenoids and sure enough the car did not misfire and idled like a cat purring. So if you haven’t already, verify that your solenoids are genuine. From my experience above, seems 2A7A was the exhaust bank B solenoid but since both of my solenoids were China aftermarket I was forced to replace both. I’m hoping the code won’t populate but I can assure the car sounds and runs better.
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