"AdBlue error message, but fault memory is empty."

Hello everyone,

Our 2012 Sharan with the CFGB engine is experiencing problems.

Symptoms:
- "Error: Blue (no engine start) in 950km (with wrench symbol)" on the dashboard.
- Autoscan with no errors.
- Disconnecting the battery does not fix the error message.
- AdBlue fill level according to scan: 71% (The tank actually only has sensors for full, medium, and empty).

According to my hazy recollection, an empty AdBlue tank will display a warning without a wrench symbol. It also says so in the instruction manual.

I would like to know what triggers this message.

History:
- February 2020:
"9567 - NOx sensor 2 for bank 1"
P229F 00 [096] - implausible signal.
"Sporadic - unconfirmed - checked since last deletion."
Error code stored in memory.
- The Nox sensor 2 (located behind the DPF) was then connected to a fuel injector cleaner and reinstalled.
- The error was gone until June.

June
The error occurred again in June.
9567 - NOx sensor 2 for bank 1.
P229F 00 [237] - implausible signal.
Warning light ON - confirmed - checked since last reset.

15733 - SCR NOx catalyst, bank 1.
P20EE 00 [237] - Efficiency too low.
Warning light ON - confirmed - checked since last reset.

- I soaked it again in injector cleaner, then rinsed it with isopropyl alcohol and thoroughly blew it dry. Error memory cleared.

Autoscan is now working without errors. The readiness check was also passed successfully. But the error message in the AI system remains.

AdBlue should theoretically last for another approximately 2000 kilometers based on mileage, and according to my recollection, it displays a different message ("Refill AdBlue") instead of "Error: AdBlue").

After the June cleaning, approximately 30 kilometers have been driven. During that time, the DPF completed its regeneration cycle. "No error codes were found in the diagnostic scan, and the warning light on the instrument cluster remains illuminated."

It's natural to assume that the lamp in the control panel is related to the NOX sensor 2. But without an error code being stored, I wouldn't want to replace the part for a price of over €500 just for the cost of materials.

Does anyone have any ideas?

Greetings.
Guste.

guste100 wrote:

AdBlue should theoretically last for another approximately 2000 kilometers based on mileage, and according to my recollection, it displays a different message ("Refill AdBlue") instead of "Error: AdBlue").

1. If the AdBlue level is low, it can only be refilled with a display showing the remaining range.
2. How do you know that the supply would be sufficient for another 2000 km?
3. If you are certain that there is very little AdBlue left in the tank, add at least 10 liters to see if the warning message disappears.

Those would be my first steps before I start replacing parts randomly. How many kilometers has the Sharan driven?

Thank you for your reply.

vag-driver wrote:

1. If the AdBlue level is running low, it can only be refilled with a specified range indication.

Thank you for the confirmation. That was also my understanding.

vag-driver wrote:

2. Where do you know that the supply should last for another 2000 km?

Between the last two fill-ups, the car was driven approximately 17,000 km. This time, it has only been driven about 15,000 km. Therefore, the estimate is that there should still be about 2,000 km worth of fuel remaining. In addition, the message that appeared was not "Refill AdBlue," but simply "AdBlue error."

vag-driver wrote:

3. If you are certain that there is very little AdBlue left in the tank, add at least 10 liters to see if the message is then cleared.

Okay, I'll probably give that a try.
The car is affected by the diesel scandal, so I get six free fill-ups from Volkswagen. Of course, they try to fill it up only when it's really empty. But in this case, I think this is also the simplest approach to try first.

vag-driver wrote:

How many kilometers has the Sharan driven?

Approximately 180,000 kilometers.

guste100 wrote:

vag-driver wrote: 3. If you are certain that there is very little AdBlue left in the tank, add at least 10 liters to see if the message is then cleared. Okay, I'll probably give that a try. The car is affected by the diesel scandal, so I get six free fill-ups from Volkswagen. Of course, they try to fill it up only when it's really empty. But in this case, I think this is also the simplest approach to try first.

If you happen to be there and find a good VW workshop, I would suggest taking the opportunity to discuss the issue with a mechanic. I've often found that they are quite talkative. You just need to trigger them.

After some research, it seems that the message isn't about the fluid level, but rather about the measured composition of the AdBlue in the tank (and therefore its effectiveness). Whether this is due to the fluid itself, the sensor, or the software is uncertain. The other errors related to NOx may be connected (possibly due to a low efficiency...).
If the AdBlue tank is almost empty, it's likely that completely refilling it with a reliable solution will help.
hg
Herbert.

Herbert wrote:

If the AdBlue tank is almost empty, it probably helps to completely refill it with reliable fluid.

Since Guste still has vouchers, I suspect the last filling was also done at VW. Let's see what he writes. Anyway, the AdBlue error without an error code is a bit mysterious.

Hi everyone,

Yes, the last two times I refilled the tank at VW dealerships, after each time there were only a few hundred kilometers left in the tank (once in Kropp, Schleswig-Holstein, and once in Villach, Austria). Therefore, I don't think the problem is caused by incorrect AdBlue.

I suspect the NOx sensor 2 is causing the car to register a lower-than-expected performance. I'll have it refilled on Friday and see if the mechanics can offer any advice. Currently, I'm planning to go back to Thomsen in Kropp. I'm open to other suggestions for places to visit in Schleswig-Holstein (feel free to send me a private message if you prefer to share them confidentially).

The car will remain parked until Friday.

Greetings.
Guste.

I'm surprised by the error message: "Engine will not start in 1000 km."

There seems to be a mistake regarding the AdBlue range. I'm keeping my fingers crossed that the notification will disappear after you refresh it.

It's a system error message related to the exhaust aftertreatment system, triggered by a component within it (e.g., fuel injector, NOx sensor, pump, pressure sensor, reversing valve, fuel level sensor, temperature sensor, etc.). See [reference/link]. SSP 424.
hg
Herbert.
,

The issue resolved itself.

The problem has really been bothering me all day.

I brought my wife's car to work today and wanted to stop and get gas on the way. "Upon starting the car at home, the expected message appeared: 'AdBlue error, engine will not start in 950 km.' The message remained displayed for the approximately 25 km to the workshop, which then showed 'AdBlue error, engine will not start in 900 km.'"
At 7:30, however, only the customer service representatives were present. The workshop opens at 8:00 AM.
I continued driving to work, feeling like something was unfinished, and after another 55 kilometers, I noticed that the display had gone out. I have no idea when it actually turned off. It was probably still on when I was at the workshop, but definitely off when I got to work. It could have been 100 kilometers driven since clearing all error codes, or just three engine starts.

A nagging feeling remains, but the important thing is that everything is back to normal.

Now all that's left to do is hope that the more thorough cleaning of the NOx sensor this time will give me some lasting relief. Otherwise, I'll have to bite the bullet and replace it. If anyone knows of reliable alternatives to the NOx sensor, which costs over €500 from VW, I would be grateful. While the appeal of alternatives starting around €180 is strong, I'm hesitant to trust products of unknown quality without any feedback.

Thank you to everyone for reading, and especially to Herbert and Andreas for your assistance.

Greetings.
Guste.

That makes me happy. At the next AdBlue refill, I would still contact VW to inquire about the cause of the error message.

I hope it stays that way!

A short long-term update for posterity:

Yesterday, I finally replaced the NOx sensor. After another two years, and with intermittent cleaning, the intervals between error messages became increasingly shorter.

After the exchange, I cleared all error codes using the Autoscanner. The Autoscanner showed no errors afterward (checked twice). However, the message "AdBlue error, engine will not start in xxx km" reappeared. This time, I paid closer attention to when it turned off: After 40 km, the message disappeared while driving normally on the highway (at a speed of 130 km/h).

I don't know why it's happening. But it seems to be normal for the AI to continue displaying an outdated/invalid message. A possible theory is that the NOx system only sends an "OK" or "not OK" message to the control unit every 40 kilometers or more.

PS: I haven't been to a VW workshop in the meantime. That's why I didn't ask any further questions about it.

Regards,
Guste.