emmisions high comes up derate and all the rest of it when I have foot off,when I get pulling again after a short while light stops flashing and all goes back to normal.Volvo have spent hours llooking at it and can not find the fault.I am just waiting for my large bill when it packs up altogether.I dont think the system is fit for the job
The system is probably cooling down when the engine isn’t working very hard: when you boot it the exhaust gas temperature rises and the chemical reaction works again. Operating the exhaust brake will also raise the exhaust gas temperature, so you could try this and see if it helps.
Some Euro VI engines actually have a throttle which restricts the flow of air through the engine on over-run to prevent the system from over-cooling.
Scania and DAF are advising Euro VI customers to choose smaller engines and work them harder, because SCR and PM filters don’t work very well unless the engine works hard. At Euro VI, a ‘lazy’ engine will actually burn fuel for no purpose other than to keep exhaust gas temperature up.
You could try some thermal wrap around the exhaust upstream of the SCR box to keep the gas hotter (DAF put this on as standard at Euro V, it’s one of the features of the ATe engine pack).
I take it that ADBLUE is the UK name for DEF here. Some guys here get problems because the regen cycle is not being completed fully, if it is interupted before it is full finished, the system does not dry it’s self out and the liquid crystalizes in the injectors etc. I had the problem with mine when I first got it but only because the previous driver had missused the system, I had it cleaned out and reset, 18 months ago and never had any problems since … Touch wood.
Thanks lads I thought I may get some info on here.
Add blue is only injected when the engine is at normal operating temperature and is dependant on fuel use and ambient air humidity.Two thermal sensors measure the exhaust gas temperature as it enters and leaves the SCR cat and the NOx sensor sits in the middle.
It sounds like the input thermal sensor is operating outside its perameters and giving a low temp signal and reducing add blue injection until you give the engine a dose of throttle which will raise gas temperature and bring it back into operating range.Meanwhile the NOx sensor is being told that the engine operating temperature is normal but due to reduced add blue injection it senses high nitrous oxide levels.
Nice one Biking I never check adblue use just put it in (I did when it was new) but I think I may be putting less in lately I will take notice see what comes up when I look at usage when I first got it thanks.`
fuse:
Nice one Biking I never check adblue use just put it in (I did when it was new) but I think I may be putting less in lately I will take notice see what comes up when I look at usage when I first got it thanks.`
Hi, I had the same message “High Emissions, Engine Derate” plus the engine management light constantly flashing, I was in Aberystwyth last week with a full load going up and down the steep curious hills, literally doing 10mph in 5th gear struggling like ■■■■. I think it used a copious amount of fuel and Adblue hence the warning messages, when I filled up in Telford with Adblue and diesel the message never came up again?.
Hi I will start by saying firstly I don’t know the Volvo system ,DAF is my thing ,apart from 1 or 2 things ,the ad-blue systems generally work on the same principle .From what has been said i gather the Volvo has only 1 NOX sensor.For a vehicle to use AD -BLUE certain criteria has to be met ,Firstly the temperature before and after the CAT has to be over 200 degrees C ,and the engine has to be under load ,example pulling up a hill fully loaded as that is when most NOX is created…take your foot off the throttle you stop creating NOX hence no AD-BLUE injection,and temperatures start dropping. Contrary to popular belief AD-BLUE is not continually injected as soon as the engine is started
Things that you may have problems with are .AD-BLUE ,is it off the correct strength,it should read 32 on the BRIC scale,if too weak then it can’t convert the NOX
Is it injecting the correct amount of AD-BLUE ,possibly some crystalised AD-BLUE restricting the amount injected
Is the CAT poisoned ,is it’s conversion rate acceptable and with in parameters…A cause of poisoning , blown turbo where oil makes it’s way in to the CAT
Lastly the NOX sensor itself ,is it too sensitive
I haven’t mentioned wiring as hey it’s a VOLVO not a DAF 
Have they contacted their tech help desk ,after all that is what it is there for
Now i know none of that has technically helped you , though saying that ,the system should be generating a fault code .The AD-BLUE SCR systems have been out long enough that 99% of the faults that can happen have been seen by dealers by now…and it isn’ t really rocket science.Now i would imagine VOLVO will be able to do a road test as DAF can where at the end of it you have GRAPH that can tell you if the CAT or NOX sensor is at fault and back pressure is also measured
Some of the things i have said you may find helpful when talking to Volvo
Thanks once again I did think that it injected all the time,I have looked on google to see if anything came up but all I get is sites where the adblue system is by passed because a fortune has been spent and it is still not fixed
We had a similar problem with a DAF 55 where I work. After a couple of trips to the local dealer there was still no reason for it to keep happening. Eventually the dealer suggested taking samples from the vehicle tank. Sure enough the two samples came back as contaminated with a high salt content. The dealer blamed our adblue supplier but we knew that the other 3 wagons in the yard were fine. Eventually the sample people said that the level of content in the DAF’s tank could only have come from urine!
I was in favour of making all our drivers take a urine test to see which one was responsible!
I wouldn’t have minded but got a mouthful of it the 2nd time I was siphoning the tank!
I found that the adblue system creates its own faults as it goes along, many daf`s in our fleet had contaminated tanks, dafg told us that it would cost £5000 to replace the pump if it got blocked with crystals from the adblue, they did however clean a small filter under the adblue tank somewhere, and that cured most of the probs. In the beginning, just after getting the adblue trucks, we had a container, with a small lid on top, this was left off, to allow free flow from the hose, it was winter, with rain, sleet, ice etc all getting into the tank, so the vehicles were contaminated for a long while, till we eventually got a proper system, a container within a container, with electric pump.
Norb…thanks for the technical jargon, gave me an idea of how the system works, you deserve a medal for your knowledge, ( one on its way )