Check-engine light, DEF light flashing, power dropping — a derate can strand a loaded truck hours from its dock. We come to you with professional diagnostic equipment, read the aftertreatment codes, and command a forced regen at the roadside when the truck's system permits it. When it doesn't, you still leave the call knowing exactly what the fault is.

What We Do on Scene

Mobile forced / parked DPF regens
DEF derate diagnosis
5-MPH / speed-limit derates
Aftertreatment fault codes (SPN/FMI)
Regen inhibitor conditions
Regen verification
HD computer diagnostics
Emissions-compliant — no deletes

What a Forced Regen Can and Can't Do

A commanded regen burns off accumulated soot. It is often the whole fix, and it is frequently the difference between a truck that finishes its route tonight and a truck that gets towed. But it is not a guaranteed outcome, and we won't sell it as one.

A regen can fail to complete for reasons outside anyone's control on the shoulder: soot load already past the point where the ECM will allow a burn, an active fault the engine is using to inhibit regeneration, a DEF quality or doser problem, a failed pressure or temperature sensor, or a filter that has reached the point of needing physical cleaning or service. In those cases the regen is not the answer, and forcing the issue isn't either.

When the Regen Doesn't Take

This is where the value actually is. If the truck won't complete a regen, that failure is information: it points at an underlying fault, and we identify it and tell you plainly what it is — the code, the live data behind it, and what it means in practice. You get documented SPN/FMI readings you can hand straight to your shop or fleet manager.

That means you decide what to do next knowing what's actually wrong, instead of paying to tow a truck to a shop that runs the same scan and charges you for the same diagnosis. For a fleet, an accurate roadside finding before the tow is the expensive part of the problem solved.

Our Scope — Straight About It

CB Roadside Assistance performs mobile diagnostics and forced regeneration. We are not a full-service diesel repair shop, and we don't pretend to be. On scene we do not perform engine, transmission or driveline repair, turbo, injector or head work, DPF removal, cleaning or replacement, aftertreatment component replacement, air-brake system repair, welding or fabrication, or anything requiring a lift, a bay or an extended teardown.

When the fault we find needs that kind of work, we tell you before you're committed to anything, and the repair is referred to or coordinated with a qualified repair technician or facility — your own shop, a fleet-preferred vendor, or someone we can point you to. We diagnose emissions systems; we never disable them.

CARB Country

California runs the strictest emissions enforcement in the nation. We work compliant, documented, and by the book — no deletes, no shortcuts — which is exactly what keeps your truck earning in this state.

Who Calls Us

Owner-operators mid-route, drayage tractors out of the Port of Oakland, rental and moving fleets, delivery contractors. If your truck regens constantly, ask about a diagnostic visit before the next derate chooses the time and place for you. Full heavy-duty roadside services → · Talk to a technician →