The importance of not ignoring DPF notices on Tier 4 models

Updated Oct 8, 2019
The DPF warning light is not one that should be ignored.The DPF warning light is not one that should be ignored.

Tiered emission standards have been around since the early 2000s when the Environmental Protection Agency finalized the rule, but what that means for your crews’ daily routine can seem obscure.

Since 2008, manufacturers have been phasing in the new emission standards to reduce nitrogen oxides. While some view Tier 4 engines as more complex, the maintenance is simply different.

Some of the changes included the types of engine oil used and the frequency of oil and air filter changes. One of the common additions to Tier 4 engines is the diesel particulate filter (DPF), which traps exhaust particles.

When a lawn mower or compact equipment is running steady RPMs and standard loads, the engine is hot enough to reduce the particulate matter to ash as it passes through the DPF, also known as passive regeneration. This is a crucial function as it keeps the machine breathing cleanly by burning off any particulate matter that could build up.

If certain conditions are not met, whether it be temperature, load or speed, for passive regeneration to occur, particulate matter will collect in the DPF. Generally, this is burned off the next time there is enough heat generated, but if a critical amount is collected, the DPF light will turn on.

Do not ignore this icon like you might with a tire pressure light on a cold morning. As soon as the alert appears, the engine’s computer will begin to decrease engine power output. When the DPF is restricted, it can lead to the mower stopping altogether and can result in major downtime and possibly calling a technician.

The light means that the machine needs parked regeneration. In order to conduct parked regeneration, park the equipment on a concrete or gravel surface. Engage the parking break, but don’t stop the engine. Depending on the make and model, starting a parked regeneration mode will vary, but it will typically take 20 to 40 minutes.

During parked regeneration do not disengage the parking brake, stop the engine or move the machine.

For more information about Tier 4, click here.

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