How to: Replacing the Adblue Heater & Temp Sensor Module

[pridyuk]

Hello, I have a 2013 passat tdi with 30k miles, and I have had a P205c (reductant tank temp sensor) CEL code for a few months now but really dont feel like spending another $600+. This past weekend my wife took the car to the dealership to do the 23N5 ecm update and as soon as she picked up the car, the display showed an add blue warning saying that i have 200 miles left to go (although the add blue tank is completely full). Is this mile countdown due to the cel code or a different issue? Is there anything i can do to reset it? This car has been a nightmare for us.
Please help

 

[r90sKirk]

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.

So, we ARE assuming that the DEF freezes when the car sits in very cold weather then?

I'm just looking for a concensus here.

Kirk

 

[aullein]

7L6-198-970A And 7P6-198-970A. Can anyone tell me the difference ?? I know 7L and 7P are the body codes for the gen1 and gen2 touaregs if that's what it might be. Wondering if one might be more updated and last longer than the other ? Looks like everyone on here that did the fix went with the 7L part#.

 

[CNGVW]

The pump has the heater right at the bottom of the suck tube in a small camber. The line to the injector at the first cat is not heated. What dos happen is when the car is shut off the pump reverses and sucks addblue and hot air back to the pump clearing the line for the next time.
I am shore the pump heater knows how cold it is so if it is frozen it will heat till it has unfrozen the chamber and then inject. When the key is off it will pull the warmed Addblue back and hot air to warm the tank for the next time.

Originally Posted by TheGrove View Post
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.

So, we ARE assuming that the DEF freezes when the car sits in very cold weather then?

I'm just looking for a concensus here.

Kirk

 

[craigpaul2000]

DEF tank heater repair

Thank you kindly for the awesome write-up. Simple job, 2 hours being extremely cautious.

Couple notes: The arrow on the large ring has no meaning. The ring is 100% symmetrical and it will go on as the threads allow. The VERY important thing is to align the insert molded screw, on the top of the heater assy, that holds the module, exactly where the rightmost hash mark is. This will ensure the module nipple is protected as you re-assemble the tank to the vehicle. I just dis-assembled the old one, took pictures of where it was and lined the new one up the same orientation.

Finally, please someone tell me the bag of random plugs and other stuff is not needed. I know I didn't remove anything like that so I cannot figure out why they are included.

Again, thanks for the walkthrough

 

[zocalo]

Forgive if I have missed a post in these pages, but I'm a bit in the dark here. The AdBlue heater/pump is part of the emission package, or so I believed. I recently had this replaced by the dealer under that premise. I took in a scan from the VAG-COM, (engine light still on) with this issue late last year. They did caution me that if they didn't get the same result it would cost me to check. However, they confirmed and ordered the parts and replaced it (took 3 weeks to get the parts). No charges. My base warranty is long over (since I have a 2012 purchased in 2011). Is this something that maybe stringent CA emission laws cover for a longer period? Like I said, I might have missed a post.

 

[Rico567]

Forgive if I have missed a post in these pages, but I'm a bit in the dark here. The AdBlue heater/pump is part of the emission package, or so I believed. I recently had this replaced by the dealer under that premise. I took in a scan from the VAG-COM, (engine light still on) with this issue late last year. They did caution me that if they didn't get the same result it would cost me to check. However, they confirmed and ordered the parts and replaced it (took 3 weeks to get the parts). No charges. My base warranty is long over (since I have a 2012 purchased in 2011). Is this something that maybe stringent CA emission laws cover for a longer period? Like I said, I might have missed a post.

There appear to have been different experiences with this issue, with some not getting the failure of this system covered, while you did. I think a good working hypothesis might be that the CA emissions warranty is involved, but I don't know for sure.

 

[maf007]

Great writeup and thanks to all contributors.
I had a 202B, bought the Toureg kit ( http://www.expressoemparts.com/oe-volkswagen/7l6198970a) and the installation went slowly but smoothly. I didn't disconnect the harness/hose under the car, but I did pop the zip ties out of the frame to give me a little extra length. Removing the bumper cover was worth the effort for me.
The tank bolts are 13mm, so I used the 13mm socket I bought in 1977 for repairing my '67 Bug!

 

[Big Red]

Guess I need to use my $500 dealership card on this.

 

[VeeDubTDI]

Guess I need to use my $500 dealership card on this.

I would wait until after you know whether A.) diesel gate compliance will force VW to fix existing AdBlue issues such as this, and B.) you are going to comply with a diesel gate recall.

I see no reason to repair this right now unless you're in an area that is subjected to sub-zero temperatures and you experience AdBlue freezing issues.

 

[maf007]

^^^ Agree. My CEL has been on a while, but I've been able to park in a heated garage this winter. I fixed it after returning from 4000 mile trip to FL only because I might head to Canada within the next month. Otherwise I'd have ignored it.

 

[heykw]

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.

What hose pics please

 

[Big Red]

^^^ Agree. My CEL has been on a while, but I've been able to park in a heated garage this winter. I fixed it after returning from 4000 mile trip to FL only because I might head to Canada within the next month. Otherwise I'd have ignored it.

It's unfortunate my wife drives the car. Just totally uncomfortable driving with the check engine light. Will likely be doing the replacement this weekend.

 

[Big Red]

Thanks!

I ended up doing this job yesterday! The write up was clear and very helpful. I pulled the bumper cover all the way off so I didn't risk accidentally popping a fastener or scratching paint.
I had some trouble removing the old unit while doing the 15 degree counter clockwise turn. I had to wiggle back and forth to get it to move.

If folks have not worked with these newer style electrical fasteners before, it would be good to point out the colored piece of the plug needs to be pulled straight out 1-2mm, then Squeezed to release the plug.

I used about 2 hrs to do the whole job as well taking my time, referencing the write up and picking up when done.

I was lucky to be at 400 miles on my Ad Blue so there wasn't much left and I didn't end up removing any fluid.

 

[mnelsonx]

My CEL has been on for about 9 months for P202b, so I finally did this job over the weekend. Couldn't have done it nearly as quickly without the guide (and would probably would have broken things), I really appreciate the time it took to put this guide together.

After using the dealership "Goodwill" package (plus a significant amount of the general Goodwill card) to buy this part, the amount of actual goodwill VW has earned with it is zero. VW really should be covering this issue and going back after the OEM for the significant number of failures.

 

[Busydiver]

My CEL has been on for about 9 months for P202b, so I finally did this job over the weekend. Couldn't have done it nearly as quickly without the guide (and would probably would have broken things), I really appreciate the time it took to put this guide together.

After using the dealership "Goodwill" package (plus a significant amount of the general Goodwill card) to buy this part, the amount of actual goodwill VW has earned with it is zero. VW really should be covering this issue and going back after the OEM for the significant number of failures.

Did you attempt to have VW pay for this? Going forward in the diesel scam story I hope, but not expecting much, that VW will be forced to cover the Ad blue system, and maybe other exhaust components under the emission warranty. This is BS that they can say the Adblue heaters are not covered under the emission warranty but in fact without the Adblue system you cannot drive the car.

 

[mnelsonx]

Did you attempt to have VW pay for this? Going forward in the diesel scam story I hope, but not expecting much, that VW will be forced to cover the Ad blue system, and maybe other exhaust components under the emission warranty. This is BS that they can say the Adblue heaters are not covered under the emission warranty but in fact without the Adblue system you cannot drive the car.

I had considered waiting for this to work itself out with VW first, but since I had to spend the dealer card on something I bought the repair kit. I figured if they changed their stance later I could be reimbursed by providing receipts. Not to mention I was really tired of looking at a CEL.

The bad news is that a couple of days after replacing I have a new CEL - P148C. It seems this is also related to the AdBlue system, but there's very little info I've been able to find on it.

 

[mnelsonx]

I had considered waiting for this to work itself out with VW first, but since I had to spend the dealer card on something I bought the repair kit. I figured if they changed their stance later I could be reimbursed by providing receipts. Not to mention I was really tired of looking at a CEL.

The bad news is that a couple of days after replacing I have a new CEL - P148C. It seems this is also related to the AdBlue system, but there's very little info I've been able to find on it.

Great news! This morning the P148C CEL cleared itself...hopefully that's permanent. I haven't had a chance to scan for codes yet, but if the CEL is out I expect it should be clear.

 

[2012passat89]

I have the added 10K thermistor and dropped it in the adblue tank but I'm still getting a P202B short to gnd, i soldered the black and white wires per another posters setup, I don't live in subzero temps but sometimes go up to the snow so I wanted to add the thermistor instead of the resistor. My CEL light came back both times i switched the wires around not knowing which was ground. did I cut the wrong wires?? http://i81.photobucket.com/albums/j215/ntrussellh/IMG_2307.jpg Any advice would be greatly appreciated.

 

[p5150]

AARGH!!!! Everything is going smooth except for the fact that I cannot get two of the locking electrical connectors to seat. They wont go in far enough to lock. They both connect to the little control modules on the front and the back of the tank.

Assistance would be appreciated!

 

[p5150]

figured it out - I sprayed the connectors with lubricant beforehand so that they would come apart easily. This worked, but it caused the gasket in some of the connectors to expand. It kept them from clicking into place.

 

[AlmondFarmer]

Just had the code come up, 2012 SE, 70k, in CA. Who or Where would know about emissions repair? Do you suspect all dealerships in CA will do the same?

 

[2012passat89]

just ordered the adblue heater kit, getting the P202B and the 10k ohm thermistor did not work....decided to fix it since I will not know when my amble gets low with that error code.

 

[aemcmg9]

You're welcome. Just be careful with how you seat the top back in. I have to take the bumper and tank down again next week so I can replace the control module. I tried to superglue the nozzle back on, but no luck. No I get a CEL for low fluid pressure and DEF stains in the driveway. No problems with driving the car though.

Do you suggest we do something differently than you adding the control module back?

 

[Phillbus]

Resistor fix

Seeing some posts saying the resistor fixes this, and some that say it did not. I have removed my DEF tank twice now and tried this fix, but my light comes back on (usually within 20 miles of driving) I really don't want to spend $500 on a new kit, if I can bypass the heater ckt. in the tank.

I'm also seeing posts that people have driven with this fault for months with no other issues. Does anyone know if the DEF system still works with this heater ckt. fault? If its just a light indicating the heater isn't working I'm not that concerned with it (in June anyway) HOWEVER if the fault means the DEF is not pumping and will plug my DPF filter, it would need to be fixed right away.

 

[clindt]

I've driven for months with the light on, but I live in Texas so it never gets to 12F, the freezing point of DEF.

And yes, it still uses DEF like before.

 

[rhauff]

I was getting the P202B Reductant Tank Heater Control signal too low code. Checked the heater resistance and it was at 10.5 ohms.

Installed the new tank heater from
http://www.expressoemparts.com/oe-volkswagen/7l6198970a ($212)
last night, the new coil is 2.5 ohms. I was able to clear the code and it has not come back, so it's fixed!

If you are wondering if this is your problem, check the resistance at the plug for the large red & white wires that go down into the tank as these are for the heater. If you have around 2.5 ohms yours is good.

 

[BarryT82]

Does anyone know if there is a difference in the 7L6 and 7P6 parts? Does 7L6 supersede to 7P6?

 

[BarryT82]

I ordered the 7L6 part from 1st VW Parts today. They price matched ExpressOEMParts.com and they accept the TDI Goodwill dealership card. Troy said they have one more in stock.

 

[BarryT82]

I received the Adblue heater from 1st VW Parts today. The install wasn't too bad. The tank was completely full so I had to drain it with my oil extractor. I used a floor jack to support the tank to remove it and reinstall it. The wires didn't have to be lengthened like some people have mentioned. The fit was just like the Passat heater that was on the car. Take pictures of your wiring and the position of the heater lid before taking it apart. While reinstalling the tank one of the rear bolts was damaged. I tried using a tap and die set to fix it, but couldn't get it to go into the hole. Luckily a friend of mine had a bolt just like it in his garage.