What is regen on a diesel truck?

Regen, short for regeneration, is a process that occurs on diesel trucks equipped with a diesel particulate filter (DPF). The DPF is designed to trap harmful particulate matter emitted from the diesel engine, but over time it can become clogged with soot. When this happens, the truck's engine control module will initiate a regen process to clean out the DPF.

There are two main types of regen processes: passive regen and active regen. Passive regen occurs when the exhaust temperatures are high enough to burn off the soot trapped in the DPF without any intervention from the engine control module. Active regen, on the other hand, is initiated by the engine control module and involves injecting diesel fuel into the exhaust system to raise the temperatures and burn off the soot.

During a regen cycle, the truck may experience decreased fuel efficiency and increased exhaust temperatures. The regen process typically takes around 20-30 minutes to complete and should not be interrupted to ensure it is successful. If a regen cycle is not completed properly, it can result in engine damage and potentially costly repairs.

It is important for diesel truck owners to understand how regen works and to follow manufacturer recommendations for maintenance and operation to ensure the DPF functions properly and the truck remains in good working condition.