CB Roadside Assistance provides 24/7 mobile roadside assistance and diagnostic services for light-, medium- and heavy-duty commercial vehicles throughout the Bay Area. We get to the disabled truck, connect professional diagnostic equipment, determine what's wrong, perform what we're qualified and equipped to perform, and give you a clear path forward when the repair exceeds roadside scope.

Roadside Assistance

Heavy-Duty Jump Starts
Commercial Vehicle Lockouts
Emergency Fuel Delivery — diesel and DEF
Battery / Starting / Charging System Testing

Mobile Diesel Diagnostics

Using professional Diesel Laptops diagnostic equipment, we connect directly to supported commercial vehicle systems to retrieve fault codes, monitor live data, perform supported diagnostic functions, and help determine the cause of a roadside failure.

Mobile Diesel Computer Diagnostics
Check Engine Light Diagnostics
No-Start Diagnostics
Engine Derate Diagnostics
DPF / DEF / SCR / Aftertreatment Diagnostics
Aftertreatment Fault Code Diagnosis
Forced DPF Regeneration — when conditions and the vehicle's system permit
Electrical System Diagnostics
J1939 / J1708 Datalink Diagnostics
No-Communication / Module Communication Diagnostics
Tractor ABS Diagnostics
Trailer ABS Diagnostics
Fault-Code Scanning, Clearing & Verification
Live Data Monitoring
Supported Bidirectional Diagnostic Functions
Minor Roadside Repairs — when within our equipment and technician capabilities

CB Roadside Assistance provides mobile roadside diagnostics and limited on-site repairs. Diagnostic service identifies faults and determines the appropriate repair path but does not guarantee that all repairs can be completed roadside. Repairs requiring additional equipment, parts, facilities, or specialized mechanical work may be referred to or coordinated with a qualified repair technician or repair facility.

Why "when appropriate" matters on a regen

If the ECM is inhibiting regeneration — a failed NOx sensor, a DEF problem, excessive soot load, a temperature sensor fault, a wiring issue, or another active fault — a forced regen isn't the fix. Diagnosing why the truck won't regen is the service, and it's the more valuable one. You get the finding either way.

How a call works

1. We come to you and connect to the truck.

Diesel diagnostic software, not a generic code reader. You get the actual fault codes, live data, and what they point to.

2. We tell you what it is.

Before anything gets towed, before anyone books shop time, you know what's wrong. That's the difference between a plan and a guess.

3. We correct it or we hand it off — and we tell you which before proceeding.

If it's something we can correct roadside, we let you know before proceeding. If it requires a larger mechanical repair, you get the diagnostic findings so you can move directly to the appropriate repair — your own shop, a fleet-preferred vendor, or a qualified mobile technician or facility we refer you to. Either way you're not paying for a tow to a shop that finds nothing, and you're not paying for a second diagnostic when you get there.

Beyond roadside scope

Straight answers, because a driver stuck at 2am deserves an accurate one. On scene we do not perform engine, transmission or driveline repair, turbo, injector or head work, DPF removal or replacement, aftertreatment component replacement, air-brake system repair, welding or fabrication, or anything requiring a lift, a bay or an extended teardown. We diagnose emissions systems; we never disable them.

Before we roll: tell us what the truck is doing

Dispatchers and drivers: send the year, make, model and symptoms ahead of the call and our technician arrives with the right diagnostic path loaded. Truck intake form →

Coverage and dispatch

Based in Emeryville, minutes from the Port of Oakland, covering the Bay Area and the I-80, I-880 and I-580 corridors. Fleet and dispatcher accounts welcome. Extended diagnostic time, additional labor, parts, and mileage outside the included service area are quoted before we proceed. Call for ETA and rate before dispatch.

Call for ETA and rate