How to: Replacing the Adblue Heater & Temp Sensor Module

Mark Neil

Member
Joined
Sep 22, 2015
Location
Massachusetts
TDI
2012 Passat SE 6 speed MT
It does fit, although with one modification.

The only difference (that I could see) was that one of the two wires (4 colored wires) was too short to make it to the plug where the NMS Passat needs it to be. Easy fix, cut off the old plug from the failed module, and used it to extend the too-short lead on the new module.

No problems at all.
 

TN2002tdi

Active member
Joined
Mar 21, 2005
Location
Mount Carmel, TN
TDI
2013 Passat SE TDI, 6-speed manual
I'm I got the CEL at 87K. The dealer quoted me $1,100+. I paid them for the diagnostic and declined the repair.

I was thinking about bypassing the sensor but I found a replacement kit (7L6-198-970a) at expressoemparts.com for $211.79 last week. http://www.expressoemparts.com/oe-volkswagen/7l6198970a I had no issues with wire lengths in this kit. One wire was actually about 1" longer than the original. I also bought a 6L fluid extractor off Amazon for $50 to siphon the adblue from the tank before I removed it. It worked great and I can use it for easier oil changes in the future.

I put the RR of the car up on a jack stand and removed the wheel and the fender liner. The screws are T25 Torx. I decided to remove the bumper cover for easier access. I left the left side of the car on the ground and removed the 5 fender liner screws required to remove the bumper cover. There is one screw that's hard to get to but you can bend the liner back enough to reach it.

To remove the bumper cover you've got to remove the taillights so you can get to 4 additional T-25 screws. You pop out the covers behind the taillights in the trunk and remove the spring-loaded plastic butterfly screw. Then disconnect the wires after you pull the lights out some. You'll then see 2 T25 screws on each side that you need to remove to get the bumper cover off. Then you need to remove 3 plastic T-12 Torx screws on the bottom of the bumper and pull the bottom of the bumper cover down and the plastic clips will pop out. You should be able to pull the bumper cover off after that. It clips on to the body along the top. You can then have an unobstructed view below the adblue tank and easily get to the bolts that hold it in place.

After you remove the 3 bolts under the tank, it will drop down and hang by the wires. With the adblue removed the tank is very light. After I dropped it down and removed the top styrofoam piece I took a photo of the tank so I could see how the wiring was routed for when I re-installed it. I then cut all of the Zip-ties and disconnecting all of the wire connectors. Some of the connectors were tough to get disconnected but you just have to look at how the release works and wiggle them some and they will come off. As stated above the hose that connects to the control module just needs a squeeze at the band holding it to the nipple and it should easily come off. The top of the tank was very dirty/crusty and I cleaned it with water and a toothbrush so it wouldn't fall into the tank when I opened it.

The 3 screws holding the control module on are 4mm Hex. After you remove them the control module will the pull off with a rocking motion. It has 2 plastic nipples w/ o-rings beneath it seated into the lid. After that I used a hammer and a Large screwdriver to tap the lock-ring loose. Then I pried the lid out with the screwdriver. It's helpful to look at the parts in the kit beforehand to see how it's assembled. The kit comes with everything you need, including new zip-ties for the wiring and plugs to keep debris out while your working. I wouldn't leave the tank disassembled long because the adblue will crystallize. I could see this causing problems with the control module. There are 2 o-rings that go between the control module and lid. Make sure they are in place before you seat it. The kit comes with new o-rings.

Putting everything thing back together was pretty simple. The bumper cover was a little fiddly but just take your time and it will pop right back on. The CEL went off after I drove the car about 30 miles the next day.

This was the first CEL I've gotten on my Passat. I've had 0 issues besides this one in over 3 years and 86K. It still looks new inside/out and runs perfectly. I experienced several issues with my old ALH before at the same mileage. It was a great car too though. It had over 260k and was still going strong before my son wrecked it.

Thanks for the write-up Docmanny. I don't think I would have had the confidence to do this job w/out your thread. And thanks to everyone else for the additional info. It was definitely worth 3 hours of my time to save $800.
 
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Mark Neil

Member
Joined
Sep 22, 2015
Location
Massachusetts
TDI
2012 Passat SE 6 speed MT
Great . . . glad it worked out for you too! And you didn't even have to lengthen one of the wiring harnesses on the new module like I did.

Great way to save money if you can.
 

CNGVW

Vendor , w/Business number
Joined
Sep 15, 2009
Location
Bob Mann Auto, 111 High St, Pembroke MA 02359
TDI
Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
I matched up the VW Passat and the Toureg pump and the body that fits in the tank is shorter did you get it to lock in the bottom of the tank???
Or do you just let it sit there??

I too saw the short lead, it is to wrap around the pump so if you go the other way it may plug in.
I think $450 for the Passat is crazy when the Tourag is half the money


It does fit, although with one modification.
The only difference (that I could see) was that one of the two wires (4 colored wires) was too short to make it to the plug where the NMS Passat needs it to be. Easy fix, cut off the old plug from the failed module, and used it to extend the too-short lead on the new module.
No problems at all.
 

Mark Neil

Member
Joined
Sep 22, 2015
Location
Massachusetts
TDI
2012 Passat SE 6 speed MT
Hi, the one I bought (part number posted somewhere in the forum!) fit perfectly in the tank, and secured (with the small turn) to the lugs in the bottom of the AdBlue tank. Maybe you got a different one if yours didn't do the same but had to "float free"?

I tried the short lead wrapped around the cap the other direction, but it wouldn't fit (would be stretched WAAY too tight if I tried to hard), so it was easier just to cut off the relevant length from the old heater lead and splice it on.

Several thousand miles now since replace and absolutely no issue. No more CEL or codes (knock on wood).
 

CNGVW

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Joined
Sep 15, 2009
Location
Bob Mann Auto, 111 High St, Pembroke MA 02359
TDI
Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
Thank you Mark
I did not use the Toureg I just benched them to see the placement. I do a lot of them so next time I will try the Toureg and add the splice job.
If you are around drop in some time.
 

Machster

Member
Joined
Sep 26, 2012
Location
Saint Louis
TDI
2013 Passat TDI SEL
I was getting the 202B fault with my Check Engine Light starting at 74k miles. I have a 2012 TDI SEL. Dealer quote was about $1200 to repair, so I figured I'd do it myself.
The part number is 561-198-970. You can get it online for the mid $400 range. I wasn't absolutely confident about my ability to do the job, so I paid a few bucks more for a return policy without a restocking fee. Here's what you get.

You will also need a torx driver and a socket wrench. You also need a hex bit. A siphon is helpful.
First step is to remove the bumper.
In each wheel well, there are 5 screws to remove. I used a torx bit with a 1/4 inch socket wrench to get in the narrow spots. It would be easier if you remove the wheels, but I didn't feel like jacking up the car. This picture was taken after removing the screws and prying the bumper away.

The top-most screw is at a tight angle
Then remove the tail-lights. Unsnap the electrical connector and unscrew the large white plastic screw. The whole assembly comes out easily.

Remove the two torx screws.

Next remove the torx screws from under the back of the bumper.
Then pry the cover off starting from each wheel well. It takes a little elbow grease, but all that's left holding the cover on are plastic clips.
Here's the Adblue tank with the cover off

There are 3 bolts holding the tank on. Two are located at the rear of the tank, and one in the front. Remove those and the tank comes right down.

Remove the foam piece and start disconnecting wires. You'll have to cut some cable ties to disconnect the mess. Don't worry, you can't reconnect the wires incorrectly later. Each clip is shaped differently. The kit comes with new wire clips also.
Now would be a good time to siphon out some of the Adblue fluid. You can use a fish tank vaccum for that (I wouldn't use it in a fish tank again though)

Now remove the three bolts holding the control module on.

Pull upwards. There is an O ring holding the module onto the tank, so you'll get some resistance.

Note the position of the arrow and the two hash marks on the tank. This will be important when putting everything back together.
Unscrew the large ring holding the heater down. Its very tight. I used a hammer and pry bar to loosen the ring. You get a new ring in the kit, so no worries.
Now pry off the top of the heater element. I used a flat head screwdriver. Remove the large O ring.

You have to rotate this piece a few degrees before it comes out.
Now that you have it off, its just the reverse to put it back together again. Beware of the arrow when you reseat the top of the heater. I made the expensive mistake of putting it the wrong place and broke the nipple off the control module ($500 retail, you can find it for $375). It also helps to have an empty Adblue tank, since it makes it lighter to reinstall on the frame.
Whole project should take less than an hour if you know what you're doing.
What about a P202A code? Same issue?
 

TN2002tdi

Active member
Joined
Mar 21, 2005
Location
Mount Carmel, TN
TDI
2013 Passat SE TDI, 6-speed manual
I matched up the VW Passat and the Toureg pump and the body that fits in the tank is shorter did you get it to lock in the bottom of the tank???
Or do you just let it sit there??

I too saw the short lead, it is to wrap around the pump so if you go the other way it may plug in.
I think $450 for the Passat is crazy when the Tourag is half the money
Didn't have any problems with the kit I ordered. http://www.expressoemparts.com/oe-volkswagen/7l6198970a
 
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klinger

New member
Joined
Sep 21, 2015
Location
Dexter, IA
TDI
2013 Passat TDI SE
I also ordered this kit: http://www.expressoemparts.com/oe-volkswagen/7l6198970a.
I installed it last Friday and it was a perfect fit without having to splice any wires.
The only comment I would add to this discussion is to disconnect the wire harnessing and the fluid line just in front of the spare tire area. There are two zip ties near there that you will have to cut, but you can use standard zip ties to re-attach the hose and harnesses.
The reason to go about it in this fashion is that then you can lower the tank out and remove it completely before having to cut a number of zip ties and disconnect multiple harness connectors. Also, doing it in this fashion means the tank is never "hanging" on the wires while you are disconnecting everything else.
All in all, this is a straight forward project. Just pay attention to the orientation of everything as everyone else has mentioned already.
Good luck!
Kevin
 
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CNGVW

Vendor , w/Business number
Joined
Sep 15, 2009
Location
Bob Mann Auto, 111 High St, Pembroke MA 02359
TDI
Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
I too disconnect the complete harness too.
I have found you can just remove the right rear tire well splash shield and just remove the torque screws that hold the bumper there. And just pull the bumper cover out a bit and
drop the tank
 

Bluto408tdi

Member
Joined
Dec 23, 2011
Location
Texas
TDI
2012 Passat TDI SE w/Nav
I got the P205B error last week. Took it to the Dealer today, and VW "goodwill"ed the repair without out even asking. 2012 TDI SE with 59k Miles.

Of note though, this is the THIRD Emission related failure I've had in 10 months. O2 Sensor in Dec 14, SCR Controller in Jan 15, and now the AdBlue tank.
 

c-wagen

Veteran Member
Joined
Oct 4, 2012
Location
Houston TX
TDI
North American Passat 2012 TDI SEL (bought back march 2018)
I did the repair today with my brother in law's help. Thanks for the write up. Some comments

1-The pump and heater cup needs to be rotated counterclockwise to unlock it from the tank to be removed (few degrees, as indicated) and the new one needs to be rotated clockwise to lock in position. I followed the recommendation of cutting the cables to remove the top of the old unit, and having good access to the old pump and heater cup to remove it.
2- I was not able to tigten the ring back to the older ring position. I used a hammer and an screwdriver to tighten it, and at some point the screwdriver began to damage the ring side steps.

The kit from expressoemparts was good, but had no instructions/references at all. All cables went back fine (correct lenght). However the new tank breather had no cap. So I used the old tank breather after removing it from the old pump. I saw some plugs to plug the adblue lines while working to avoid cristallizatiion. Used some, but not all (some I could not see were to put them... Maybe this is a multiple car kit?)


I installed it, now I'm waiting to see when the code goes out (if I dont kill it before with Vagcom)

UPDATE: after 28 miles the Check Engine Light went off (yay!). Cost: 233.28$ (Pump and heater), 8.63$ (a small transfer fluid pump from Walmart), and 17$ for 2.5 gal of DEF, Peak brand (it is cheaper in Walmart!). Total less than 260$, and three hours (taking it easy). Thanks again!
 
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Shortydap1mp

Active member
Joined
Jul 8, 2014
Location
Texas
TDI
2013 Passat tdi SEL
How often do I need add the def fluid? I just got a 13 Passat and found the fluid fill haven't had it long just wondering.
 

TheGrove

TDIClub Enthusiast, Veteran Member
Joined
May 17, 2006
Location
S Central PA (Breezewood)
TDI
2012 Passat SEL Premium Opera Red - Dieselgate Fix, KermaTDI Tune, 2004 Passat GLS Northern Green-RIP
It should last for the 10,000 mile service interval. Mine was supposed to be filled at 180,000 miles and the 1,500 mile countdown just started and I'm 1,800 miles to the next service.

It used to last longer but I've been noticing over the last 10 months or so it seems to be going thru it a bit faster than before.
 

silvrmax04

Active member
Joined
Dec 18, 2011
Location
MD
TDI
2012, 2015 Passat TDI SE
I was getting the P202A code. Replaced the heater tank as in this thread. Easy. Straight forward. Erased the code, added 2.5 gal of def fluid and now I get a P20E8 code and I have 150 miles left to add more fluid. What's going on. Any one know?
 

silvrmax04

Active member
Joined
Dec 18, 2011
Location
MD
TDI
2012, 2015 Passat TDI SE
Found the problem. I broke the nipple on the control module. Just my luck. I knew it was too easy. Another $365. It didn't buil pressure so it sen the code and the add fluid was due to it all leaked out. At least I know the problem. I did not remove the bumper. Only the 4 trim screws. I even markd the arrow. I now adjusted it as close to the inside as possible. It prob happened when I installed it the first time and forgot the foam. Still cheaper than the dealer and I will know next time. And there will be a next time.
 

Roger108

New member
Joined
Nov 17, 2015
Location
NY
TDI
2012 Passat TDI
Hi guys- new here. Replaced my heater per the error code, cleaned nox sensor both errors are now gone. I have 35 miles left in my def range. Drove it 4 cycles and reset the scr lock when the car prompts me that no restart... which gives me 35 miles def range every time I reset the lock. Total driven since heater replacement was 60 miles. Still getting Adblue warning. Any ideas or recommendations?

Also checked tank heater/ tank level in vcsd everything looks right. No more fault codes.
Also did the Adblue reset via the instructions in vcsd.

I'm stuck. Really appreciate the help :)
 

kconnor123

Member
Joined
Jun 23, 2015
Location
midwest
TDI
2012 VW passat
Found the problem. I broke the nipple on the control module. Just my luck. I knew it was too easy. Another $365.......

Yeah, same scenario here. After replacing the heater I'm getting the p20e8 code and it says to refill my tank when it's still about half full. Like you said it was really easy for me as well. I re dropped the tank and I don't see anything broken, the connection to the nipple on the control module is very loose though but it is still attached and does seem broken. How do take that thing off to see if the nipple is broken? Maybe it is leaking air from a bad deal under the control module. Anyhow, away on business now and will revisit when I return.

Frustrating!
 
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Machster

Member
Joined
Sep 26, 2012
Location
Saint Louis
TDI
2013 Passat TDI SEL
Thanks for the great Sticky! I was getting the P202A code and ordered a replacement heater from Keffer VW. It took two hours total to replace, including siphoning and cleanup. Great resource.
 

silvrmax04

Active member
Joined
Dec 18, 2011
Location
MD
TDI
2012, 2015 Passat TDI SE
I replaced the module and all is good now. The add fluid wentbawaynin about 3-5 miles. Over 50 miles now and back to normal. I believe the module is actually a pump. If your hose is loose or not on it will leak and you will see the white crystal everywhere. Check all your wiring connections too.
 

aullein

Veteran Member
Joined
Mar 5, 2014
Location
Melbourne Fl
TDI
2012 Passat TDI SE 6Speed Manual
So in what way is this new repair kit ( 7L6-198-970a ) superior or better than the old part (561198970)? Just curious if anyone knows if they found the reason why the old one was prone to fail??
 

kconnor123

Member
Joined
Jun 23, 2015
Location
midwest
TDI
2012 VW passat
Ok my saga is over thank goodness. Turns out when i put the control module back on the new heater assembly i forgot to put the little tiny washer gasket on the smaller nipple thus it would not create a seal and i got the reductant low pressure p20E8 code. I disassembled and reassembled with the gasket and it still wouldn't clear the code and the countdown with low DEF continued.

I ordered a new controller(pump) and replaced it and viola! after about 1 mile of driving all was cleared.

I assume what i did was burn up the controller unit? When i didn't have it sealed with that little gasket. Funny, i was reading so much about the broken nipple problem i spent so much time ensuring i didn't break that i forgot about that gasket and ended up toasting the pump anyhow.

Oh well, ya live and ya learn. I'm about 650$ into it, still cheaper than the 1200$ the dealer wanted.
 

TDI_Brad

Veteran Member
Joined
Jul 25, 2012
Location
SC
TDI
Passat TDI SEL
I will have to give this a try. I have codes P205B and P20EE. Maybe this fix will clear both codes. Anyone else had P20EE for the SCR NOx catalyst bank 1 error?
Would a stage 2 tune deleting out the AdBlue system make this fix not necessary?

Sent from my iPhone using TheChive - KCCO!
 

titleist1

Veteran Member
Joined
Sep 12, 2013
Location
Baltimore
TDI
2013 Passat SE TDI
Stupid plastic nipple

Found the problem. I broke the nipple on the control module. Just my luck. I knew it was too easy. Another $365. It didn't buil pressure so it sen the code and the add fluid was due to it all leaked out. At least I know the problem........... It prob happened when I installed it the first time and forgot the foam. Still cheaper than the dealer and I will know next time. And there will be a next time.

I did the exact same thing....I had just replaced the sensor and checked it with vagcom before mounting the tank. Re-installed everything and realized I forgot the styrofoam. I broke it on the re- install with the foam in place.

Thought I was going to get away real cheap with just replacing the $10 thermistor but now I need the control module because of that stupid plastic nipple. :mad:
 

r90sKirk

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Oct 21, 2003
Location
CedarTuckey, Michigan
TDI
All TDI's - No gassers! Luxo-Tourer = 13 Passat (hands down, the nicest car we've ever owned), Most fun = MK4 Golf
Regarding this issue, my question is this:

Everyone states that if you live in the colder climate states you need to fix this issue to keep the adblue from freezing, what prevents the adblue from freezing when the car is not running, as I assume this is not always heating when the car is not running or on?

Kirk
 

atc98002

Veteran Member
Joined
Nov 24, 2006
Location
Auburn WA
TDI
2014 Passat TDI SEL Premium (sold back), 2009 Jetta (sold back), 80 Rabbit diesel (long gone)
My guess is there's an time period after cold start that is allowed by regulation to get the emissions systems up to speed. AdBlue would be one of several things that have to warm up, as well as the cat converters and so on.

If I remember correctly, there's a small AdBlue tank near the injector that can likely be warmed quickly and begin injecting the fluid. That would allow more time to thaw out the remainder of the system.
 

titleist1

Veteran Member
Joined
Sep 12, 2013
Location
Baltimore
TDI
2013 Passat SE TDI
"Everyone states that if you live in the colder climate states you need to fix this issue to keep the adblue from freezing, what prevents the adblue from freezing when the car is not running, as I assume this is not always heating when the car is not running or on?"

I had this same thought while reading the initial threads about the heater failure, nothing prevents it from freezing while the car is not running. I imagine the folks up north could have a nice 3-4 gallon block of frozen DEF if their car sat for a few days in the dead of winter. I wonder how long the heater in the tank would take to melt that.

My guess is VW doesn't really care about it not injecting any DEF while it is frozen until the heater kicks in and melts it. I imagine the fault codes generated were there to satisfy the fail safe requirements for the emission system not to ensure proper injection operation.
 

titleist1

Veteran Member
Joined
Sep 12, 2013
Location
Baltimore
TDI
2013 Passat SE TDI
Ordered the replacement pump from VW Vortex Sat night and it arrived yesterday afternoon. $354 plus shipping. Got it put in at lunch today and all is back together and working. I made sure to put an extra zip tie to hold that tubing pretty securely so it didn't pull on that plastic nipple.

I got about an extra gallon out of the tank too which made it easier to put back up without the fluid sloshing from one end of the tank to the other.

One note on the plastic bumper trim. Mine has three clips underneath across the back that have a torx head screw (smaller torx than the wheel well torx) that tightens & loosens the clip action. It was easier getting them in and out by backing out that screw a little. You don't have to take it all the way out.
 

TheGrove

TDIClub Enthusiast, Veteran Member
Joined
May 17, 2006
Location
S Central PA (Breezewood)
TDI
2012 Passat SEL Premium Opera Red - Dieselgate Fix, KermaTDI Tune, 2004 Passat GLS Northern Green-RIP
Regarding this issue, my question is this:

Everyone states that if you live in the colder climate states you need to fix this issue to keep the adblue from freezing, what prevents the adblue from freezing when the car is not running, as I assume this is not always heating when the car is not running or on?

Kirk
You don't need the whole tank unfrozen. As I remember the pickup is next to the heater so just a short amount of time will thaw enough to start injecting. As you and others noted it probably doesn't start injecting right away. There is a warmup procedure the car follows that is temperature dependent. I would believe that when it is cold enough extra fuel is injected to reduce the NOx and also get the engine warmed up quicker. Another item if you listen to the car when you shut it off you can her the pump sucking the DEF back into the tank so the lines are clear and nothing is in them to freeze. The lines are also heated so the DEF will flow to the injectors once it is started to be pumped.
 
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