Aftertreatment 1 DPF Outlet Temperature Sensor - Voltage Below Normal

Cummins fault code 1672 indicates: Aftertreatment 1 DPF Outlet Temperature Sensor - Voltage Below Normal. It is a moderate-severity fault in the aftertreatment or emissions system.

Yes, short-term driving is typically safe with fault 1672, but the fault will illuminate the Check Engine Light and must be diagnosed soon. Monitor for power loss, unusual noises, or gauge changes and pull over if conditions worsen.

Repair cost is approximately $300-$800 including parts, labor, and any dealer programming required. DIY repairs (sensor replacement) fall at the low end; pump, aftertreatment, or ECM work falls at the high end and usually requires INSITE diagnostic software.

California's heavy-duty OBD regulation requires the system to flag the PM filter before its filtering capability drops — from cracking, for instance — enough to push PM emissions past 0.07 g/bhp-hr, or past the applicable standard plus 0.06 g/bhp-hr, whichever is higher (Title 13 CCR 1971.1, section (e)(8.2.1)). Where no credible failure could reach that level, it must instead flag the case where no detectable filtering is happening at all. This threshold comes from the heavy-duty OBD regulation, which covers 2010 and later heavy-duty engines. If your engine is in a pickup at or under 14,000 lb GVWR it is certified under the separate medium-duty rule instead, so treat this as the design intent rather than your engine's exact limit.