With the advent if euro 5 emission within the UK ,Honda had to adopt the DPF (Diesel Particulate filter) on all Honda Accords sold in the UK. The I-CTDI on the European continent was already using DPF for several years so the data and experiences were helpful in designing the 8th Generation DPF. The Honda DPF system on the 8th Generation has not seen major failures yet in the UK.When problems have arisen Honda have been proactively fixing issues and evolving into a refined system via ECU updates and software fixes. At this moment in time DPF are actively and widely hated technology, you don’t have to go far within search engines to see endless posts on all major car forums to find owners venting their frustration at the cost fixing the DPF system. Owners have taken to extreme measure of removing DPF, deleting the DPF function within the ECU and tuning them for more power, with varied success and not to mention engine failures. Some manufacturers have failed to deploy reliable system some are getting there gradually, and some have nearly perfected the system. On a personal level and seeing these cars for four years I would say the Honda system really good. This is provided all owners are aware of the caveats and proactively know what they can do to limit DPF related issues you may never encounter any problem on a STOCK engines. Owners of a tuned ECU you don't have any leg to stand on for support and warranty via Honda. This thread is to give HK members and all potential Accord diesel owners an insight how the Honda DPF system works and quash any misconception regarding the DPF system. Figure one shows the two separate warning lights that can be illuminated for this system. A) At less than 7g the DPF system will automatically clean itself whilst driving once the DPF is up to correct operating temperature. B) At 7-11g the system will attempt to clean itself whilst driving regardless of DPF temperature. C) At 11-15g the system will alert the driver by blinking the DPF warning light on the dashboard. The owner should then follow the driving instruction explained in the owner’s manual to help clean the system. What is it? This requires a constant speed of at least 37mph to be maintained for up to 15 minutes. The best thing you can do is go for a 20 mile motorway run. Majority of the times this cures the warning. D) Above 16g the system will shut down to prevent damage due to a blockage occurring and the warning light will then be permanently illuminated.(Picture A) .If the owners continues driving with this light on permanently then the message may change to the exclamation mark symbol.(Picture B) .At this time you will need to go to the Honda dealer for them to hook up the HDS system to check whether you has a system fault or blocked . If they find the system above 16g then carry out a forced regeneration and check if there are any outstanding software and ECU updates. Tips A few tips you can do to keep the DPF troublefree. Always carry a litre of DPF compliant oil in the boot as stated here Avoid mixing oils which are no compliant as it leads to issues. You should not be making this mistake.Make sure all the drivers of your car are aware of this so careless mistakes can be avoided. Engine Oil Level Increase on the i-DTEC Engines get your dealer to look up their database to ensure your car has the latest software updates and patches to ensure troublefree motoring. Ask them nicely to show you how it’s done they will be glad to show you.