[adriang]

So I was reading online that if you have errors with the active tank level sensor you may add some resistors to the wiring to trick your car into thinking the sensor is okay or the sensor may be covered in lots of dried up DEF and maybe giving it a wash would cause your check engine light to go away.

In my case my active level sensor went bad (code 4BAC) and upon reading online, BMW wanted to charge $2400USD to replace the active tank completely as they don't sell just the sensor. Did some more digging and found a post online where someone replaced the active tank sensor with a VW part on an x5d, but not on the 335d. Given the similarities between the 335d and the x5d I thought I'd give it a try too.
So I replaced the sensor with the VW part...and no more check engine light. It was around $330CAD+tax from the VW dealership. The VW part # is 7L6 198 970 A. There are two versions of this part make sure it matches the above and then its plug and play. No cutting or splicing wires of required.

Alternatively this sensor may be available here too: http://xemodex.ca/ca/product/def-scr...it-for-bmw-x5/ for the part

Instructions
Step 1: jack up your car safely as you will start to work from underneath the car

Step 2: Lower the exhaust pipe from its rubber holders and unscrew exhaust protective plate about halfway on your car (4 large hex screws). Support the exhaust to prevent it from breaking

Step 3: remove the heat shield directly below the trunk I think size 8mm or 10mm nuts. In my case the nuts were really rotten and I replaced some with large galvanised washers and nuts afterwards

Step 4: you will now see the bottom of the active tank. There are two 17mm nuts you need to loosen that will let you get access to the sensor from the trunk.

Step 5: go to the trunk and remove the black metal plate under the rug giving you acess to the top of the active tank and sensor. There are around 10 size 8mm or 10mm nuts. You can't remove this plate if you skip step 4 since the 17mm nuts are holding the tank to the black metal plate in your trunk. Be careful of the antenna wire attached to the metal plate.

Step 6 unscrew 3 bolts using an allen key driver from the top part of the sensor


Step 7 unscrew the lid of the sensor by hand (or using flathead and hammer since mine had a ton of dry DEF)

Step 8 replace with the new sensor. It looks like a basket, will get a photo of it once I log onto a computer


Step 9 scan your car for codes and put your car back together

Lastly: some may be able to get this covered under emissions warranty depending on their state and mileage.
also to avoid from sensors going bad, I read that the solution is to not overfill the def tank.

I apologize if it doesn't make sense, I wanted to take pictures as I went along but my phone froze from the cold... So if you have any questions let me know

[andrewb_1985]

This is a great thread. Good to know. I would never have called VW for the part. Just wondering if you know where you found the info on people who added resistors to trick the sensor? That seems like an easy cheap fix that would last forever.
I would guess however, that if system always thinks the tank is full, the passive tank would never get the signal to transfer into the active tank. But would be an interesting project.

[adriang]

i found it here https://xoutpost.com/bmw-sav-forums/...r-failure.html

Some were mentioning that tricking the sensor is not a good idea if you drive in areas where it goes below freezing

[andrewb_1985]

Originally Posted by adriang

Some were mentioning that tricking the sensor is not a good idea if you drive in areas where it goes below freezing

Good to know. So how come VW calls this part the heater and temp sensor repair kit? Does it also have the level sensor?

[335dlci]

I'm not sure about canada, but we have extended warranty for the def tank in the us.

[andrewb_1985]

Originally Posted by 335dlci

I'm not sure about canada, but we have extended warranty for the def tank in the us.

How long was the warranty extension in the US?

[kbsilver]

Pretty sure it's 10 years or 120K miles.

[335dlci]

Originally Posted by kbsilver

Pretty sure it's 10 years or 120K miles.

correct. also are the NOX sensors.

[adriang]

Originally Posted by andrewb_1985

Good to know. So how come VW calls this part the heater and temp sensor repair kit? Does it also have the level sensor?

If I recall correctly all sensors are in this part

Originally Posted by 335dlci

I'm not sure about canada, but we have extended warranty for the def tank in the us.

Not sure about Canada but when I did this replacement the recall wasn't active.

[demon]

Originally Posted by adriang

So I was reading online that if you have errors with the active tank level sensor you may add some resistors to the wiring to trick your car into thinking the sensor is okay or the sensor may be covered in lots of dried up DEF and maybe giving it a wash would cause your check engine light to go away.


Step 4: you will now see the bottom of the active tank. There are two 17mm nuts you need to loosen that will let you get access to the sensor from the trunk.

Step 5: go to the trunk and remove the black metal plate under the rug giving you acess to the top of the active tank and sensor. There are around 10 size 8mm or 10mm nuts. You can't remove this plate if you skip step 4 since the 17mm nuts are holding the tank to the black metal plate in your trunk. Be careful of the antenna wire attached to the metal plate.

Step 6 unscrew 3 bolts using an allen key driver from the top part of the sensor


Step 7 unscrew the lid of the sensor by hand (or using flathead and hammer since mine had a ton of dry DEF)

I am just starting to research my 4BAC code. reading a thread -
https://www.bimmerfest.com/threads/x....667126/page-5 - I would like to try adding the three resistors the author mentions. My question to you - can I just remove the cover in the trunk to access the wiring? Your photo above is it from the bottom or from the trunk with the cover removed? Which wire in your photo is the sensor wire? I am hoping it is one of the four wire connector easily accessible.

[adriang]

Originally Posted by demon

I am just starting to research my 4BAC code. reading a thread -
https://www.bimmerfest.com/threads/x....667126/page-5 - I would like to try adding the three resistors the author mentions. My question to you - can I just remove the cover in the trunk to access the wiring? Your photo above is it from the bottom or from the trunk with the cover removed? Which wire in your photo is the sensor wire? I am hoping it is one of the four wire connector easily accessible.

I cannot remember exactly. But I think you have to drop the exhaust on the 335d and the def tank to get to the sensors. You cannot gain access through the trunk. It is welded.

I think I did the resistor trick on an x5d and that was easier to get to.. sorry my memory is faded on the topic now

[POBEP]

Originally Posted by grotto

Will this part work on 335d? I just had the Reductant active tank temperature sensor come on with every start over the weekend and was going to do this myself rather than another $2k at indie or dealer. Can't pothole, have emissions. Car killing my wallet but great engine.

E90 335d 16196765825
E70 x5d 16196765824

remember to
- be extremely gentle disconnecting metering line from SCR Delivery Module (Pump)
- wash tank/drain/transfer lines with distilled water
- run ISTA metering quantity test - after you assemble and install tank but before you put exhaust/bumper in-place

While ISTA test designed to validate DEF quantity pumped - it adds instant assurance against potential leaks in metering line connections

TL; DR
I just finished SCR Delivery Module (Pump) replacement due to previous crappy SCR tank replacement job by BMW of San Rafael.
I followed BMW Service manual that calls for rear bumper and exhaust removal.
Overall this SCR job was very time consuming (lots of steps) yet relatively simple job.

[DougNBodie]

The BMW part is listed at FCP Euro for just under $450 and with a lifetime guarantee that is hard to beat.


https://www.fcpeuro.com/products/bmw...sch-f01c600252

[DougNBodie]

Originally Posted by grotto

I had this issue and purchased a NEW - OEM VW Audi 7P6198970A Diesel Exhaust Fluid DEF Heater from Ebay for $106, replaced it with my mechanic and the SES went away.

Well, that's better then me. I changed it out with the BMW/Bosch part and the light went out immediately. So I put the car back together and within 10 miles the light came back on. I'm Pissed to say the least.

[LapyBimmerPost]

For others who find this thread and read to the end I wanted to add a few key learnings to the steps after following this for my 2011 335d:

Step 4/5: Trunk black plate is not welded in but feels like it if you start by just removing the in trunk 10mm nuts; just follow the steps to drop the muffler to remove the SCR 16mm nuts AND remove one of the cable tray 10mm Z bracket nuts from underneath (passenger side), so you don’t break the plastic attachment point on the tray. I didn’t understand how the cable support tray bracket bolted to the trunk black pan and forced it. SCR tank bolt support nuts were 16mm on my vehicle (not 17mm)

Step 8: I couldn’t figure out how to remove the sensor basket. I ended up watching a YouTube video of someone doing a Touareg to see that you need a small CCW turn to free the basket. Also here, pay attention to the top mounting orientation with either the yellow dot or arrows to markings on the SCR tank so that alignment going back together is understood.

I know the thread is old but it is still relevant. Now there is also the option of using the Bosch part: F01C600301 which is what I purchased (from RM European Auto Parts) as it was less expensive than the VW named parts.

[demon]

I finally got around to replacing this sensor. I had been just keeping the active tank full and that would clear the CELL. But then it didn’t, so I had to do this. Like everything, BMW not difficult but also not easy. It just took a lot longer than I thought it would or should.

Couple of notes, first thing is sizes of tools needed, I had to make a run to the auto parts store to buy the torx sockets.
Exhaust system from the back forward.
First hanger torx socket t-10 (female)
Second one in 13mm socket
Third one in 18mm
Plate across the pipe, t45 torx {male)
Heat shields 10mm and 8mm
Two nuts holding rear cover down 16 mm – these two nuts hold the DEF tanks up. When the second comes off the tanks will fall. I was glad I had just loosened the exhaust; it held the tanks up.

Thanks to lapybimmerpost note about the quarter turn to free the basket. Drain most of the DEF out so you can reach to the bottom to twist.
I bought the sensor off of amazon for $240, when I just went to check the price it came up as $231