The Diesel Oxidation Catalyst (DOC) is a critical emissions component in the aftertreatment system of Cummins X12 and X15 engines. Positioned early in the exhaust stream, the DOC helps reduce harmful pollutants before they reach downstream components, supporting cleaner exhaust flow and proper emissions system operation. The Cummins X12, X15 DOC OEM 5509700RX is designed to meet factory requirements, making it a dependable replacement option when maintaining or restoring exhaust system functionality.
• Reduces harmful exhaust gases by converting carbon monoxide and unburned hydrocarbons into
less harmful compounds, supporting cleaner exhaust output and proper emissions control
• Designed for Cummins X12 & X15 engines ensuring correct fitment, proper sealing, and seamless
integration with the factory exhaust and aftertreatment system
• Supports downstream emissions components by lowering pollutant load early in the exhaust flow,
helping the DPF and SCR systems function as intended
• OEM-grade construction (5509700RX) providing dependable durability, consistent operation, and
compatibility with original emissions system hardware
• Helps maintain emissions system stability by supporting balanced exhaust conditions and reducing
the likelihood of emissions-related fault codes
Replacing a worn or restricted DOC with the Cummins X12, X15 DOC OEM 5509700RX from Tamerx Diesel Parts helps restore proper exhaust treatment and protect the integrity of the entire aftertreatment system. Choosing an OEM-matched DOC filter ensures reliable operation, supports emissions compliance, and helps keep your engine running smoothly under everyday driving conditions.




























































