This Is OnSite Diesel Solutions LLC

Hey there! I'm a mobile diesel mechanic located in Loma Rica, and I cover all of Yuba and Sutter County. I handle everything from heavy equipment and big rigs to tractors, farm gear, and medium-duty commercial diesel trucks. My go-to tool is top-notch dealer-level computer diagnostics, which helps me pinpoint problems accurately. No guessing here—I get straight to the source.

Here's what happens when you call me out. I come to where the machine is—whether it's in a field, yard, or job site. I hook up my gear, run some diagnostics, and start tracking down the issue. I don't swap out parts until I'm sure of the problem. I'll explain what I'm finding as I go, and I'll put together a report that's easy to understand. You'll know what went wrong, why it happened, and what steps we need to take next.

Heavy Equipment:

I work on loaders, backhoes, excavators, dozers, and graders—basically, any machine that breaks down on the spot. I mostly deal with brands like CAT, Volvo, John Deere, Case, Komatsu, and Hitachi.

I've had times when a machine wouldn't start even though the batteries were fine and the terminals were clean. There was this one CAT loader where the ground strap seemed okay but turned out to be faulty—it was hidden under the cab. Another time, a Case backhoe was losing power when it was working hard. No error codes popped up, but the fuel pressure was dropping at the rail. I figured out it was because of a weak lift pump that couldn't keep up.

Even if there's no error code, I can still track down the problem. I run diagnostics, check the voltage, fuel, signals—whatever the system requires. I keep digging until I figure out what's wrong.

DEF issues pop up all the time. Sometimes the system doesn't reset after a fix, or it derates even when everything seems okay. I look into sensors, wiring, fluid quality, and run regen tests if needed. I don't just wipe the codes—I figure out why they're there and make sure it's fixed. Plus, I can update you on your filters—percentages, soot load, ash level—so you know exactly what's going on. This way, you get a clear picture of how much life your filter has left and what to expect down the road.

Big Rig Truck Repair:

I work on big trucks like Kenworth, Peterbilt, Freightliner, International, Volvo, and Mack. When I get called out, it’s usually because the truck won’t start, there’s a DEF fault, a brake issue, or some annoying electrical problem that keeps coming up. I head out to wherever the truck is—whether it’s in the yard, at the shop, or just parked somewhere.

I've come across trucks that wouldn't start after the shop put in a new starter. It ended up being a bad ground. I've also seen DEF systems that still act up even after swapping parts. I always run diagnostics, check the wiring and sensor data, and make sure the issue is confirmed before replacing anything.

I can let you know what's up with your aftertreatment system—like filter load, regen history, and fault count—so you're in the loop about what's happening and what's next. I don't just clear codes and hope it works out. I track it down, make sure it's right, and break it down for you. I also take care of PMI inspections, DOT-certified checks, CARB compliance, and oil changes. If it's parked and needs some work, I've got it covered.

Tractor and Farm Equipment Repair:

I fix tractors, harvesters, sprayers, and other farm gear, whether they're broken down in the field or just sitting in the yard. I mostly deal with brands like John Deere, Case IH, New Holland, Kubota, and Massey Ferguson.

When I get called in, it's usually because something won't start, there's an electrical glitch, a fuel problem, or a hydraulic issue. You know, stuff like leaky oil seals, weak lift, or slow response are pretty typical. I go through and check the pressure, flow, how the valves are working, and the condition of the cylinders. If it's not running smoothly, I dig into it until I figure out what's wrong.

I've got all the tools for checking out Tier 4 systems, and I can track down problems without any guesswork. If there's a derating issue, I dig into the aftertreatment system—like checking the DPF status, DEF quality, and sensor readings—to figure out what's going on.

I don't just skim through and fix things. I break down what went wrong, why it happened, and what steps we need to take. If something's on hold and needs a look, I've got it covered.

Medium-Duty Commercial Truck Repair:

I work on box trucks, service trucks, flatbeds, and other medium-duty diesels, mostly in the Class 4 to Class 6 range. I handle brands like Ford, Chevy, Ram, Isuzu, Hino, and Freightliner M2. If it's parked and not running properly, I've got it covered.

People call me for problems like no-starts, check engine lights, DEF faults, and those pesky electrical issues that keep popping up. I've got full diagnostics for Cummins, Duramax, Powerstroke, and other systems. I don’t just guess—I track it down.

I take a look at the voltage, fuel pressure, signals, and sensor data. If it seems to be losing power, I dive into the aftertreatment system—checking out the DPF status, DEF quality, and sensor readings—to figure out what's up. If it's not starting, I go through everything step by step until I find the issue.

I also take care of PMI inspections, CARB compliance, and oil changes. If it's parked and needs some work, I've got it covered.

Diagnostics:

Nowadays, most trucks and gear are all about electronics, sensors, and emissions systems. You can't fix what you don't get, which is why diagnostics are so important. It's not just about plugging in a scanner and checking codes. It's like walking into a dark room and finding that one loose wire hidden behind the wall. You don't just guess—you trace it. You pay attention to what the system's saying, even if it's not giving you any error codes.

I see diagnostics as a chat. The machine isn’t speaking in words—it’s all about voltage, pressure, signals, and data. I know how to tune in. I focus on what’s important, skip what’s not, and keep digging until I figure out what’s wrong.

If there's a no-start, a derate, or a recurring fault, I don't just clear the codes and cross my fingers. I make sure to check out the issue, explain why it happened, and lay out the next steps.

Each scan includes a health report with actual numbers and findings, explaining what's working and what's not. The report is emailed to you and comes with the service. No extra fees, no nonsense—just a straightforward account of what I observed and tracked.

“Need mobile diesel repair in Yuba/Sutter County? Visit our Services page.”

“OnSite Diesel Solutions LLC – Mobile Diesel Diagnostics & Repair”