How to Perform a Manual Regen

In this module, we'll review the basic steps required to activate your truck's regen cycle.

Our trucks utilize a filter system called DPR, or Diesel Particulate Reduction.  To put it simply, the DPR system collects the ash and soot from the exhaust to regenerate and burn off.This regeneration process prevents harmful emissions from being released into the air and the black smoke that is commonly seen emitted from diesel vehicles when accelerating.

How Does a Regen Work?

Depending on the trucks driving habits, the truck may automatically regenerate, or go into “regen mode”. This happens when there is a large amount of soot collected in the filter that needs to be burned off. The good news is when the truck is operating normally, the DPR filter is continuously regenerating thanks to a built-in filter. During this phase, the engine may make a different noise, idle speed may increase, and a slight burning smell is released.

An automatic regen does not require any action by the driver, other than making sure the truck stays ON. It is safe to continue driving as normal. A regeneration cycle typically takes between 10 and 30 minutes to complete.

What Happens When the Truck Does Not Auto-Regen

Trucks that incur many starts and stops on short journeys at low speeds are often unable to meet the requirements necessary for the filter to automatically regen and clean itself. Extended conditions like this may require a manual regn by the driver. This is often indicated on your dashboard by a warning light and in some trucks an audible warning.

To know if the truck needs a manual regen, we’ll look to the dash to find the DPR filter clogging level display. To do this, we’ll click the mode button in the lower left corner of the dash until we’re on the correct screen. If the truck were to automatically regen, it would do so when showing 2-4 bars. However, once the display shows a 5th bar, this is when a manual regen is required.

To perform a manual regen, we’ll need to pull over and park the vehicle in safe place with the exhaust facing away from people and flammable materials, such as dry, grassy fields. Once parked, apply the parking brake. Next, put the truck in neutral. With the engine on, we’ll need to disable the PTO and we won’t be able to clean any toilets during this time. Next, we’ll look to the dash and make sure the engine is warmed up to the appropriate temperature and that the DPR warning light is indeed flashing. If the light is flashing, we’ll go ahead and press the manual regeneration button on the dashboard.

The engine will automatically be brought to a preset speed and the DPR warning light will remain on without flashing. We’ll now wait 10-30 minutes for the regen cycle to complete. If this process takes longer than 30 minutes or the check engine light comes on, call the shop immediately for assistance. We’ll know the procedure is complete when the DPR filter warning light turns off and the engine returns to idle speed.

So, what does that mean for our drivers?

It’s important to make sure you always perform a manual truck regens when it signals. Failure to do so will cause the truck to go into turtle mode and limit your speed below 15-20MPH, as well as cause further damage to the DPR system, which will be extremely expensive to fix.