Our mobile techs are equipped with dealer-level diagnostic tools and common replacement parts to fix emissions issues on-site—no tow required.

1. Exhaust Gas Pressure Sensor (EGPS)
   Located on top of most Cummins engines, this sensor monitors backpressure in the EGR system. Failure can block regen. Often repairable roadside.
2. EGR Valve
   A stuck or failing EGR valve can prevent exhaust flow and trigger regen faults. In some cases, we can free or service the valve in the field.
3. Differential Pressure Sensor (Delta P Sensor)
   Measures pressure across the DPF. A failed sensor can falsely indicate restriction. We carry replacements for common engines.
4. NOx Sensors
   Faulty NOx readings may prevent regen and trigger derate. We diagnose sensor performance and clear codes when appropriate.
5. DEF Level & Quality Sensor
   This sensor, often part of a module in the DEF tank, monitors DEF volume and purity. When it fails, it can cause false low DEF or contamination codes—even when the tank is full. These include SPN 3031, SPN 1761, and SPN 1569.
6. Engine Codes That Matter
   Knowing which fault codes indicate a simple forced regen vs. those that require shop service helps us determine if your issue can be fixed roadside.

• SPN 1921 FMI 0 or 16 – Moderately severe DPF restriction. Often cleared with a forced regen.
• SPN 1922 FMI 16 – Critical DPF restriction. May require DPF removal/cleaning or replacement, followed by resets.
• SPN 1569 FMI 31 – Engine derate active due to emissions fault.
• SPN 3031, SPN 1761 – DEF level/quality sensor faults that can block regeneration.

If you’re showing SPN 1922 or other regen-blocking fault codes, and a roadside repair isn’t possible, we’ll dispatch a heavy-duty wrecker to tow your truck to the repair shop of your choice.