your problem is most probably the dosing unit(common fault) ..that's the small unit beside the exhaust and has the braided pipe going to the injector ..
first of make sure you have the ignition off otherwise you will store a fault and will need davie to clear it ...take off 2 torx screws and remove cover ,then 4 torx screws and nuts to remove the dosing unit , 19 mm spanner to remove air pipe ,14mm spanner for inj pipe ,then use you hands to carefully remove ad blue pipe ..you then have 4 small torx screws that you take out remove the inj unit then carefully remove the small diaphram ,and rinse the housing out in hot water (it will probably be crystallised),then reverse said procedure ...after all that remove the braided pipe and the actual injector in the exhaust (you may need to apply heat to the small inj bolt )and flush through with hot water and blow through with an air line and refit if clear ...
then you need to go on a good 30 to 40 min run to get the parameters required for the system to operate ...it would take too long to explain how the system operates ,but quickly ,the beforeand after cat sensors need to be over 200 degreed c ,the engine needs to be under load ,and as long as it isn't -5 i think ,can't remember as ad blue won't work at -5 as ther is no need for it...
there is a new modified dosing module out ,though the software needs to be updated to operate it
norb
December 2010
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