astra J code 55 by Englishkeymaster » Tue Oct 02, 2018 4:59 pm Just a quick one re 1.7cdti denso - SH7059 - this code (which illuminates on dash) insinuates a dpf problem, in this case the user unknowingly bought a car with it gutted and constantly regenerating. Vauxhall Code 55 - YouTube. How to clear error 55 on a Vauxhall / Opel without going to the garage. Running the engine on a run of around 45 minutes clears mine in 5th gear at 2,500 WWy4rJH.