DEF and DPF derate on heavy equipment
Why a Tier 4 machine cuts its own power, the faults behind most derates, what EPA changed in 2025, and what to do before anyone clears the code.
Read the derate guide →Short, practical guides for operators, owners and fleet managers. What a fault actually means, what to do first, and when it is time to call a repair truck.
Machine down right now? Skip the reading and call. The phone is answered 24/7.
Each guide links to the service page behind it, so you can see what the repair involves when it is time to call.
Why a Tier 4 machine cuts its own power, the faults behind most derates, what EPA changed in 2025, and what to do before anyone clears the code.
Read the derate guide →How to make the machine safe in the first ten minutes, why nobody uses a hand to find a leak, what not to do, and what to tell the repair truck.
Read the hose guide →Tell us the machine, the symptom and where it sits. If we can help, you will know on the first call. If we cannot get to you in time to do any good, we will say that too.
(904) 496-2937