Frequently Asked Questions

Clean Truck Check is the California Air Resources Board's (CARB) heavy-duty vehicle inspection and maintenance program. It requires periodic emissions testing for heavy-duty diesel and other non-gasoline vehicles that operate in California, performed by a CARB-credentialed tester. The goal is to catch emissions-related problems so they get repaired. For the official details, see CARB's Clean Truck Check program page.

Right where your truck is. Foxx Inc is a mobile, CARB-credentialed tester (Tester ID E275460) based in Fremont, open 24 hours. Book online with the truck's location, call (909) 569-3922, or email carbctc@foxxinc.us.

Any vehicle that needs one. That includes diesel trucks and tractors, box trucks, dump trucks, buses and shuttles, diesel motorhomes and RVs, agricultural vehicles, and trucks registered in other states. If CARB requires a test for your vehicle, we can come to it and test it — $79.

According to CARB, a non-gasoline motorhome with a GVWR over 14,000 pounds that is registered in California needs Clean Truck Check. Recreational motorhomes test once a year; commercial-use motorhomes test twice a year. Gasoline motorhomes aren't covered. See CARB's motorhome page for the official details.

CARB's motorhome guidance is written for California-registered motorhomes, and its pages aren't fully consistent about RVs registered in other states — so check CARB's Clean Truck Check pages or call CARB for your situation. If you do need a test, we can come to your RV park or campground and do it, 24 hours a day.

Yes. We're mobile, so we come to wherever the RV is parked — RV park, campground, storage lot or your driveway — as long as we're allowed to be there. Just give us the location when you book.

We'll explain what the test found and can diagnose the engine and emissions systems on your diesel motorhome, then quote any repair before work starts.

CARB defines which vehicles are covered, and it generally applies to heavy-duty, non-gasoline vehicles operating in California — including many trucks registered out of state. Because the exact rules depend on your vehicle, check CARB's vehicle owner information or call us and we'll point you to the right place to confirm.

It depends on the test method that applies to your truck. An on-board diagnostics (OBD) test is typically a short visit. Older trucks that need a different test method can take longer. We'll give you a time estimate when you book so you can plan your day.

The truck, the keys, and your vehicle information — VIN, license plate and registration. If you've had previous test results or received a notice from CARB, have those handy too. Park somewhere safe where we can reach the truck, and tell us about any warning lights.

We'll explain what the test found in plain language. Many issues show up as stored fault codes or emissions-related readings. From there, you can have us diagnose the cause and give you a repair estimate. Nothing is repaired without your approval.

Yes. We're a full-service mobile truck mechanic, not just a tester. If testing points to a problem, we can move straight into diagnostics on the spot instead of sending you somewhere else.

In many cases, yes. After diagnosis we'll give you a written estimate. If you approve it, we can often do the repair right at your truck. If a repair needs a shop or is outside what we do, we'll tell you so upfront.

No. CARB's annual compliance fee is paid by the vehicle owner directly to CARB through its reporting system. Our $79 price covers the mobile testing service. Check CARB's website for current fee information.

Testing frequency is set by CARB and depends on the vehicle type and CARB's current schedule, which has changed over time. Check CARB's vehicle owner information for your truck's deadlines. We're happy to schedule reminders when you book with us.

Yes. Our Shell Rotella T6 Full Synthetic Diesel Oil Change starts at $600. Let us know the viscosity your engine manufacturer specifies and we'll confirm it when you book.

Yes. Our Delo SynBlend Diesel Oil Change uses Chevron Delo 400 XLE SB SynBlend 15W-40 heavy-duty diesel engine oil and starts at $500.

There's no single number that fits every truck. The right interval depends on your engine manufacturer's recommendations, the oil you use, and how the truck is driven — idle time, loads, grades and short trips all matter. Start with your engine manufacturer's service schedule and adjust for severe duty. We can help you set an interval that fits your routes.

Both are established heavy-duty diesel engine oil brands. The most important thing is using an oil that meets the specifications your engine manufacturer requires. Some owners have a brand preference or fleet standard; if you don't, we can explain the difference in our two options and their pricing.

Draining the old oil (we take it away for proper disposal), replacing the oil filter, and refilling with your chosen diesel oil to your engine's specified capacity — all at your truck's location. We'll also note anything obvious we see, like leaks, and tell you before recommending any additional work.

Because the part that seems obvious isn't always the cause. Warning lights and symptoms can have several possible sources. A proper diagnosis finds the real problem, so you don't pay for parts you didn't need and the truck doesn't come back with the same issue.

It depends on the problem and on which lights are on. A flashing light, a red stop light, a derate, low oil pressure or overheating warnings mean you should stop safely and call for help. For a steady amber light, get it checked soon — small problems tend to get more expensive when ignored.

Yes. When you book diagnostics or repair online, you can upload photos of your dashboard or the problem area. It helps us bring the right tools and parts.

Yes. We diagnose first, explain what we found, and give you an estimate. No repair work starts without your approval.

We focus on diagnostics, mechanical and electrical repair, fluid and filter service, inspections and preventive maintenance for commercial trucks. If you're not sure whether we handle a specific job, call us and describe it — we'll give you a straight answer.

Our inspections are a hands-on look at the condition of your truck's major systems, focused on maintenance: what's worn, what's leaking, what's due soon and what can wait. You get a clear list of findings. These are general maintenance inspections, not a government certification.

For most owner-operators, yes. When your truck is your income, unplanned downtime costs more than the repair itself. Regular oil changes, inspections and early diagnosis help catch problems while they're smaller and cheaper, and let you choose when the truck is off the road.

Yes. Owner-operators are a core part of our customer base. We explain findings in plain language, confirm pricing before work begins, and try to get you back on the road quickly.

Yes. We work with small fleets and local businesses that run commercial trucks. We can help schedule Clean Truck Checks, oil changes and maintenance across several vehicles so they're not all out of service at once.

Yes. Book the first truck online and note how many vehicles you have, or call us and we'll schedule them together.

We're a mobile service, open 24 hours, 7 days a week. Book online or call (909) 569-3922 so we can plan when to come to your truck. For urgent problems, call — we'll tell you how soon we can get there.

Yes. The online form takes about a minute: pick the service, enter your truck, where it is and a message, plus your name and phone. We'll call to confirm, come to the truck, and you pay when the job is done.

We currently accept: Cash, Major credit/debit cards. Call us if you have questions about fleet billing.

No. You pay when the service is completed at your truck.

Call us as early as possible — since we drive to you, early notice helps us plan our route. See our cancellation policy for details.

Our Clean Truck Check test is $79, and we come to your truck. You pay when the test is done. CARB's separate annual compliance fee is paid by the vehicle owner directly to CARB and isn't included.

Our Delo SynBlend diesel oil change starts at $500, and our Shell Rotella T6 full synthetic diesel oil change starts at $600 — done at your truck's location. The final price depends on your engine's oil capacity, filters, and any additional service needs. We confirm the price before we start.

Commercial trucks vary a lot. Oil capacity, the number and type of filters, and engine configuration all affect the cost. The starting price gives you a clear baseline, and we confirm your final price before we begin.

It depends on the problem and the truck. We'll confirm diagnostic pricing before we start, and after diagnosis you get an estimate for the repair. You approve costs before work goes ahead.

We're a mobile service based in Fremont and come to trucks throughout the East Bay and wider Bay Area — including Newark, Union City, Hayward, San Leandro, Oakland, Pleasanton, Livermore, San Jose, Berkeley and Concord.

Yes — that's how we work. We don't have a shop you need to drive to; we come to your truck at your yard, job site, parking spot or home. Just make sure it's a safe place to work and we're allowed to be there.