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Hello and Welcome to justanswer...
My listings indicate that the 128 fault code is related to the operation - or faulty operation of the EGR valve.
You will need to remove it and give it a good clean... sometimes this works well - and clean out the ports as well -- they get sooted / caked up.
Check all the piping (associated ) etc and clean as needed - - and then refit and retry.
Hopefully all will be well -- but if not - you will need to renew the egr valve.
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Kind Rgds,.... MIKE
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