AdBlue countdown - NOX Sensor errors
My G350 (2010) has been showing the AdBlue warning - no start in xxx miles. Diagnostics show problems with NOX sensors. There is plenty of AdBlue in the tank. My local Mercedes dealer wants £2,000 to replace both NOX sensors and clean up the wiring to these sensors. I am looking for a better (cheaper) alternative! Possibilities: 1) ignore and hope to reset the countdown (it does reset sometimes at random), 2) try fuel additives to clean out the NOX sensors (maybe Forte Exhaust Crystal Preventor), 3) Attempt self repair to clean out the NOX sensors, 4) Cough up the money to Mercedes (very unappealing), 5) sell the car (also unappealing). Any better ideas.....am keen to sort this very annoying problem out!
PM me the vin from the car and I will have a look at options
NOX sensor replacement should be relatively easy
Need details to check correct part but I am assuming it will be A000 905 36 03
MB want £500 plus each
There is a seller with brand new genuine ones on eBay for sub £200 each and possibly a good deal less with a cheeky offer!
He has a few also!
https://www.ebay.co.uk/itm/166750415509?epid=12023499335&itmmeta=01J46VH...
But also need to check as some of these need modified sensor to make them right
Also might just be worth inspecting and cleaning the wiring plugs prior to replacement!
Just been told that a lot of these early blutec G's have a recall on them for engine software issues and some require NOX sensor replacement as part of the recall, so again let me have details and I can check, although the dealer really ought to have checked already but sometimes gets missed!
That's interesting! I would have expected my Mercedes dealer to be aware if there's any open recalls, but my level of confidence in them is not that high!
That's interesting! I would have expected my Mercedes dealer to be aware if there's any open recalls, but my level of confidence in them is not that high!
That recall is just an ECU firmware update, to make the ECU more tolerant ot failing NOX sensors. The sensor is still failing and the problem will reappear in a few months. Many MB dealers don't have technicians trained on G's and they rely on generic MB knowedge which is generally good enough. Certainly good enough to look it up on the computer and see that there is an ECU upgrade.
Also, the blocked injector is easy to remove and clean, but it won't stop the failing sensor problem.
To be fair John it all depends on your dealer
The title of the SM is ECU software
But the scope of potential works is much bigger including replacing NOx sensors if required, ECU if required and much more
Has your been in for this? It was launched in October 23
Has your been in for this? It was launched in October 23
No! I had the ECU upgraded and it was OK for a couple of months (or less) then started again. tbf, I stopped using main dealer from the time I got it - too many half baked (and expensive) trips before that on various MB cars and in my experience they didn't work on enough Gs and its just inconvenient to get it to Reading, Oxford or Beaconsfield. I never for one minute thought I would be eligible for any MB recall on a 2012 car. I use my local garage for everything, and in the past STAR Motors in Reading or John Griffiths.
Anyway, its not relevant now. I had it deleted properly. Being Euro5 didn't cut the mustard for ULEZ so there was no point to keep it going. Someone else can easily restore it if they want, but it will mean new sensors, level sensor, possibly adblue heater.
An update, after I re-scanned with my Launch - not a fancy model (it's the Creador Elite 2.0).
Got the following messages:
- 163400 No CAN message was received from control unit N118/5 (AdBlue(R) control unit)
- 16d400 The test of the AdBlue system has not been carried out. The remaining driving distance is limited.
- 153800 Internal fault in component NOx sensor downstream of SCR catalytic converter
I tried to clear these messages with some success.....the countdown for AdBlue has stopped showing now on starting the vehicle! Fingers crossed this stays. Is it possible that the diesel software upgrade (that dealer said they applied) has solved these various AdBlue/NOx errors?
Definitely confused, but feeling better as no need to spend time & effort fixing the NOx sensors (in the short term anyway).
interesting, I thought it was only a software update; it did lower fuel consumption, since the update I see sometimes 28mpg on local runs in the countryside.
I had the same as the 3rd error code for sure.
The ECU upgrade just makes the ECU more tolerant of the sensor output. So if the sensor is supposed to read 100% but drops to 97% before the ECU reports an error, they said it was OK to deteriorate to 90% before reporting the error. 9i'm making the numbers up for illustration)
The sensor is still breaking down and soon enough it will drop below that 90% and the same error will return. There are 2 NOX sensors - one before the CAT and one after. Its reporting the one after. But you would replace both if you were going to do that.
I found some replacement NOx sensors online. Do you know whether there is any special software re-setting to be done along with the physical change out? Am asking as I can probably do the change out but don not have any advanced tool to reset the engine/exhaust settings.
I found some replacement NOx sensors online. Do you know whether there is any special software re-setting to be done along with the physical change out? Am asking as I can probably do the change out but don not have any advanced tool to reset the engine/exhaust settings.
someone else should confirm, but I don't believe there is any pairing required. I think its a straight sensor replacement. certainly was the case for an adblue injector which I replaced.
JOIN THE GWOA
This website and forum are provided for the benefit of enthusiasts and owners of all Mercedes Benz off road vehicles, in particular the G Wagen. The costs of development, upkeep and provision of the site are met entirely by the annual subscriptions of club members. If you are using the site and are not a member of the G Wagen Owners Association please consider joining. You will have access to areas on the site that are not open to non members, to club trips and meetings and to technical assistance. In addition your contribution (only £25 annually) will help us maintain and develop our website for future users.
Who's new
- Robert Maune
- Jack Gilliland
- apbW460
- cloudburst
- Mike242
Thanks for your encouraging reply! Are there are special tools needed to replace these NOX sensors? Also, I've seen separately that the AdBlue injector can get clogged up with crystalized residue which does not help the whole AdBlue/NOX setup. Would you recommend cleaning this injector out also?