420801

misguided_will · 12-14-2020, 09:09 PM

hi all

anyone has this code before?

420801 - Electric motor clutch 2 sensor: Supply short circuit to B+.

What does it mean and is it anything i need to worry about?

thx

SlowMo · 12-15-2020, 02:21 AM

Quote:

Originally Posted by misguided_will

hi all

anyone has this code before?

420801 - Electric motor clutch 2 sensor: Supply short circuit to B+.

What does it mean and is it anything i need to worry about?

thx

I'd like to know as well, I had the same shadow code. I just had a transmission replacement done with a brand new unit, 2016 340i

misguided_will · 12-15-2020, 02:25 AM

Quote:

Originally Posted by SlowMo

I'd like to know as well, I had the same shadow code. I just had a transmission replacement done with a brand new unit, 2016 340i

Yikes. Was it replaced under warranty?

What symptoms have you noticed? My car seems to drive OK except I've kind of noticed it feels like the gearbox disengages and there's a hesitation to re engage when I get back on the gas.

Is there confirmation what is meant by a "shadow code"? From google, some says its like a preliminary code when the car is yet to confirm it as a fault while others have said it's like cache memory

SlowMo · 12-15-2020, 02:29 AM

Quote:

Originally Posted by misguided_will

Yikes. Was it replaced under warranty?

What symptoms have you noticed? My car seems to drive OK except I've kind of noticed it feels like the gearbox disengages and there's a hesitation to re engage when I get back on the gas.

Is there confirmation what is meant by a "shadow code"? From google, some says its like a preliminary code when the car is yet to confirm it as a fault while others have said it's like cache memory

Yes thankfully completely covered by warranty. Symptoms were a high pitched 'whine' especially in 2nd gear, also noticeable in other gears but was the loudest in 2nd. I also noticed the shifts were not as smooth, and my car only had 50K kms

After the replacement the noise is gone, shifts are much better, but I noticed this shadow code. I cleared the code and it hasn't re-appeared yet. I couldn't find any info on the net about this code.

misguided_will · 12-15-2020, 02:40 AM

Thanks for sharing. I've just hit 20,000 km so relatively low mileage and I dont drive it very hard apart from the occasional boot down a local street.

For me there were 2 records of the shadow code.

Do you have any other error codes?

I got the below

4203F1 unknown
420801 - Electric motor clutch 2 sensor: Supply short circuit to B+.
420822 unknown
421732 unknown

SlowMo · 12-15-2020, 02:42 AM

I had the 420801 exactly like yours with the same description

I also had 421062 - unknown

Would love to find info on this if possible before I flash MHD and XHP

misguided_will · 12-15-2020, 02:44 AM

Quote:

Originally Posted by SlowMo

I had the 420801 exactly like yours with the same description

I also had 421062 - unknown

Would love to find info on this if possible before I flash MHD and XHP

Yes same. I'm holding off flashing until I get more details.

I've emailed the dealer to ask what I should do given there were codes which I've since however cleared

Shall report back with updates

BMWILUVU · 12-15-2020, 11:55 AM

Are all of you on tunes?

misguided_will · 12-15-2020, 01:57 PM

Quote:

Originally Posted by BMWILUVU

Are all of you on tunes?

Was on piggy only

No date of the fault code tho

BMWILUVU · 12-15-2020, 04:37 PM

Quote:

Originally Posted by misguided_will

Was on piggy only

No date of the fault code tho

Looks like the code has to do with gear engagement and your sensor for clutch 2 looks like its gone bad. Now I've never heard of a sensor on each individual clutch plate so I would imagine this is indicating mechatronics maybe one of your solenoids is on the way out. That would sound more reasonable to me and why so many of you have this code since its a part which known to wear. Your shadow codes could have to do with your AT unit exceeding ratings and may have to do more with your tunes.

SlowMo · 12-15-2020, 08:59 PM

Quote:

Originally Posted by BMWILUVU

Are all of you on tunes?

No tune, 100% stock

chinniciF32 · 12-21-2020, 10:09 PM

I have the same exact shadow code although I'm not stock, what would be the solution to fixing this code? Hopefully a transmission service?

SlowMo · 12-22-2020, 11:59 PM

A BMW techie replied to me, he said not to worry since it is shadow codes, and could be related to adaptations.

I have cleared my codes using MHD a couple weeks ago, it hasn't returned since. Car moves and shifts perfectly fine. I'm 100% stock as well, never tuned.

kianf22 · 01-02-2021, 06:01 AM

Anyone have 421892 shadow code? Car flashed with xhp stage 3

fie method · 09-13-2021, 02:08 AM

Updating this post to help anyone with similar transmission codes. I bought my 2016 340i at 40k miles, and pulled these codes at 50k:

420801 - Electric motor clutch 2 sensor: Supply short circuit to B+
421732 - Unknown

I replaced the following with 100% oem parts in hopes to fix the codes. Also ZF recommends this done every 50k miles, less if tuned:

transmission pan/filter
oil
mechatronic sleeve

7 months later and still no codes. 6 months with xhp stage 3 on mhd e40 tune, trans runs flawlessly. I really recommend only using oem parts/fluid.

12-14-2020, 09:09 PM	#1
misguided_will Second Lieutenant 57 Rep 299 Posts Drives: 2018 BMW 340i M Sport Join Date: Jan 2009 Location: Sydney iTrader: (0)	420801 - Transmission fault code help hi all anyone has this code before? 420801 - Electric motor clutch 2 sensor: Supply short circuit to B+. What does it mean and is it anything i need to worry about? thx __________________ 2018 F30 BMW 340i M Sport Injen EVO intake, OEM 437m rims, Catted VRSF dp, Magnaflow catback, Activ8 piggyback, Pedalbox.
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12-15-2020, 02:40 AM	#5
misguided_will Second Lieutenant 57 Rep 299 Posts Drives: 2018 BMW 340i M Sport Join Date: Jan 2009 Location: Sydney iTrader: (0)	Thanks for sharing. I've just hit 20,000 km so relatively low mileage and I dont drive it very hard apart from the occasional boot down a local street. For me there were 2 records of the shadow code. Do you have any other error codes? I got the below 4203F1 unknown 420801 - Electric motor clutch 2 sensor: Supply short circuit to B+. 420822 unknown 421732 unknown
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12-15-2020, 02:42 AM	#6
SlowMo New Member 6 Rep 20 Posts Drives: E90 N54 and E36 M52B28 Join Date: Nov 2009 Location: South Africa iTrader: (0)	I had the 420801 exactly like yours with the same description I also had 421062 - unknown Would love to find info on this if possible before I flash MHD and XHP
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12-15-2020, 11:55 AM	#8
BMWILUVU Lieutenant Colonel 809 Rep 1,597 Posts Drives: 340ix Join Date: Mar 2017 Location: The Boibs iTrader: (0)	Are all of you on tunes?
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12-21-2020, 10:09 PM	#12
chinniciF32 Noob 70 Rep 254 Posts Drives: f32 n55 Join Date: Feb 2020 Location: Stamford, CT iTrader: (0)	I have the same exact shadow code although I'm not stock, what would be the solution to fixing this code? Hopefully a transmission service?
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12-22-2020, 11:59 PM	#13
SlowMo New Member 6 Rep 20 Posts Drives: E90 N54 and E36 M52B28 Join Date: Nov 2009 Location: South Africa iTrader: (0)	A BMW techie replied to me, he said not to worry since it is shadow codes, and could be related to adaptations. I have cleared my codes using MHD a couple weeks ago, it hasn't returned since. Car moves and shifts perfectly fine. I'm 100% stock as well, never tuned.
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01-02-2021, 06:01 AM	#14
kianf22 First Lieutenant 64 Rep 348 Posts Drives: 2020 BMW M240i Join Date: Jul 2019 Location: Southern California iTrader: (1)	Anyone have 421892 shadow code? Car flashed with xhp stage 3 __________________ Pure800 - DS2 HPFP - Nostrum S1 - ER Catless DP - Remus Non-Resonated Catback - BM3 Flex Fuel Kit - Ross V1 VTA PCV - Custom Tunes on MHD/BM3 - xHP Stage 3 - TCKline SA/DA Coils - Apex ARC8s - Vicrez Carbon Fiber CSL Trunk - ALP Laser System - Escort Max 360c with Blendmount + more... \| IG: kianf22 \|
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09-13-2021, 02:08 AM	#15
fie method New Member 0 Rep 27 Posts Drives: 2016 340i, 2015 M3 Join Date: Aug 2020 Location: Huntington Beach, CA iTrader: (0)	Updating this post to help anyone with similar transmission codes. I bought my 2016 340i at 40k miles, and pulled these codes at 50k: 420801 - Electric motor clutch 2 sensor: Supply short circuit to B+ 421732 - Unknown I replaced the following with 100% oem parts in hopes to fix the codes. Also ZF recommends this done every 50k miles, less if tuned: transmission pan/filter oil mechatronic sleeve 7 months later and still no codes. 6 months with xhp stage 3 on mhd e40 tune, trans runs flawlessly. I really recommend only using oem parts/fluid.
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