What is the fine-grained topic of the following text: John Deere PowerTech Interim Tier 4 engines at or above 175 hp (130 kW) can go up to 15,000 hours between Diesel Particulate Filters (DPF) ash removals, which means less downtime and more efficiency on the job. Only return the topic.
Diesel Particulate Filters maintenance duration in John Deere PowerTech Interim Tier 4 engines.