Diesel particulate filters (DPFs) are an item that is seeing increasing failure rates, especially on Island as they often do not have chance to clean themselves due to many people using their vehicles for short journeys, the vehicles do not reach the temperature required for the filters to regenerate.
If this goes on the filter becomes blocked, leading to poor fuel economy and performance and often activating the vehicles limp mode.
By eliminating the DPF from the system it removes this restriction. A change in The ECU must also be performed to release the vehicle from limp mode and to prevent any error codes being shown.
Exhaust gas recirculation (EGR) valves are also problematic for many vehicles, often failing and causing poor running and fault codes to be thrown, again failure often occurs due to short journeys and pottering around town.
There are two possible methods to eliminate this problem. One method is to tell the ECU to keep the EGR closed. Providing the EGR is mechanically sound this is sufficient. If the EGR has already failed, complete removal may be necessary. This then requires a deletion from the ECU to prevent it from throwing a fault code saying it is missing from the system.