Jaltest Marine Vessel Diagnostics

Marine diagnostics demand a different level of commitment from your tools. Saltwater environments corrode connectors, engine rooms are tight, and when something breaks on the water, the clock is ticking in a way it never does in a truck bay. Jaltest marine diagnostic coverage gives you OEM-level access across 86 marine engine and systems manufacturers, 1,557 models, 3,120 technical data resources, and 2,165 interactive wiring diagrams -- all through a single diagnostic platform.

Diesel Truck Diagnostic Tools has supported marine technicians with Jaltest solutions since 2016. Whether you run a full-service marina, a mobile marine repair operation, a boatyard, or a commercial vessel fleet, this page walks you through everything Jaltest covers on the water and why it matters for your business.

Marine Diagnostic Coverage at a Glance

These numbers grow with every software update. Cojali releases three marine coverage updates per year, adding new manufacturers, model years, and diagnostic functions. Your Jaltest subscription keeps you current automatically.

Three Marine Subcategories

Jaltest organizes marine diagnostic coverage into three subcategories. Each one addresses a distinct segment of the marine industry with its own manufacturers, engine types, and diagnostic requirements.

Outboard Engines

Fourteen outboard engine manufacturers are covered, from small fishing boat motors to high-performance offshore powerplants. Mercury, Yamaha, Suzuki, Honda, Evinrude/BRP, Tohatsu, and more. Outboard diagnostics cover engine management, fuel injection systems, ignition timing, trim and tilt controls, and emissions systems on four-stroke models. If your shop services outboards, this subcategory alone justifies the marine module.

Inboard Engines

Thirty-four inboard engine manufacturers are covered -- the largest marine subcategory by far. This spans diesel and gasoline inboard engines from Volvo Penta, Cummins, Caterpillar, MerCruiser, Yanmar, MAN, MTU, John Deere, Scania, and dozens more. Coverage ranges from pleasure craft sterndrive systems to commercial workboat propulsion and superyacht engine rooms. Inboard diagnostics include full aftertreatment access on Tier 4 marine diesels, marine gear and transmission controls, and vessel management system integration.

Watercraft / Jet Ski

Personal watercraft diagnostics cover BRP/Sea-Doo, Kawasaki, Yamaha, Scarab, and Rotax engine platforms. PWC diagnostics include engine management, fuel system calibration, and electronic throttle control. A smaller segment, but a growing one -- and a segment where most shops currently have zero diagnostic capability beyond reading basic fault codes.

Full Diagnostic Capabilities on the Water

Jaltest marine diagnostics go far beyond reading and clearing fault codes. Here is what you can do with the marine module connected to a vessel.

Fault Code Reading and Analysis

Read active and stored fault codes from every supported ECU on the vessel. Jaltest provides OEM-level fault code descriptions -- not generic aftermarket translations -- along with probable causes, related technical service bulletins, and step-by-step troubleshooting procedures. Clear codes after repairs and verify they do not return.

Real-Time Sensor Data

Monitor live data from every sensor connected to the engine and vessel management systems. Coolant temperature, oil pressure, fuel rail pressure, exhaust gas temperature, boost pressure, raw water intake temperature, transmission oil temperature, battery voltage, and dozens more parameters stream in real time. Record data sessions for later analysis when troubleshooting intermittent issues that only show up at cruising speed or under load.

ECU Data and Parameters

Access the full parameter set stored in each ECU. Engine serial numbers, calibration versions, operating hours, fuel consumption totals, maximum RPM history, overheat event logs, and more. This data is critical for pre-purchase surveys, warranty documentation, and maintenance record verification.

Component Activation (Actuator Tests)

Activate individual components to verify they respond correctly without waiting for the engine to call for them naturally. Cycle fuel injectors, activate cooling fans, test warning buzzers, operate trim tabs, engage and disengage marine gear, and test exhaust flap actuators. Component activation tests isolate electrical and mechanical failures faster than any other method.

Calibrations and Programming

Perform ECU calibrations that normally require a dealer visit or the manufacturer's proprietary software. Injector coding, throttle position sensor calibration, idle speed adjustment, marine gear engagement timing, and trim system calibration are all accessible through Jaltest on supported models. This capability alone can save your shop thousands of dollars per year in outsourced programming.

DPF Regeneration (Diesel Marine)

Tier 4 marine diesel engines use the same aftertreatment technology found in on-highway trucks -- diesel particulate filters (DPF), selective catalytic reduction (SCR), and diesel oxidation catalysts (DOC). Marine DPF regeneration requires specific conditions and procedures that differ from truck applications. Jaltest supports forced DPF regeneration, aftertreatment system diagnostics, soot level monitoring, and SCR efficiency testing on supported marine diesel engines.

Parameter Modification

Adjust configurable parameters stored in the ECU. Idle speed, maximum RPM limits, alarm thresholds, engine derate settings, and other operator-adjustable values can be modified through Jaltest on supported platforms. This is especially valuable for commercial vessel operators who need to configure engine behavior for specific operating profiles -- trolling speeds for fishing vessels, load management for workboats, and performance tuning for patrol boats.

Interactive Wiring Diagrams

Access 2,165 interactive wiring diagrams directly within the Jaltest software. These are not static PDFs -- they are navigable, zoomable, and linked to the diagnostic data. Click on a sensor in the wiring diagram and Jaltest shows you the live data from that sensor. Click on a connector and see the pin assignments, wire colors, and circuit descriptions. When you are tracing an electrical fault in a corroded marine harness, this integration between diagnostic data and wiring information saves hours.

Troubleshooting Guides

Jaltest includes manufacturer-specific troubleshooting procedures that guide you through diagnosis step by step. These are not generic flowcharts -- they are developed from OEM service information and tailored to the specific engine platform you are working on. Each guide tells you what to check, what values to expect, and what to do when a test fails.

Marine-Specific Challenges Jaltest Addresses

Saltwater Corrosion and Electrical Integrity

Marine electrical systems face constant assault from salt air, spray, and humidity. Diagnostic connector pins corrode, ground circuits develop high resistance, and CAN bus communication becomes intermittent. Jaltest marine diagnostic routines include communication integrity checks that help you distinguish between a genuine ECU fault and a connection problem caused by corroded pins or degraded wiring. The interactive wiring diagrams show you exactly where to check for corrosion-prone connection points on each platform.

Access Constraints and Working Conditions

Marine engine compartments range from spacious commercial vessel engine rooms to impossibly tight stern compartments on center console boats. Jaltest runs on a standard laptop that you can position wherever you have space -- on the dock, at the helm, or on the engine room deck plates. The Jaltest Data-Link interface is compact enough to connect in tight spaces, and cable extensions let you run from the diagnostic connector to a comfortable working position.

Coast Guard Compliance and Documentation

Commercial marine vessels operating in U.S. waters must comply with Coast Guard and EPA regulations covering emissions systems, safety equipment, and engine maintenance documentation. Jaltest generates diagnostic reports that document fault code history, aftertreatment system status, and engine operating parameters -- the kind of records that Coast Guard inspectors may request during vessel surveys. Having digital diagnostic records on file demonstrates due diligence and proper maintenance practices.

Multi-Engine and Multi-System Vessels

A typical vessel has two main engines, a generator set, and potentially a bow thruster, stabilizer system, and vessel management system -- each with its own ECU, potentially from different manufacturers. A sport fisher might run twin Yamaha outboards. A commercial trawler might have Caterpillar mains with a John Deere genset. A superyacht might have MTU mains, Kohler generators, and a ZF marine gear system. Jaltest covers all of these from a single interface. One tool, one cable set, every system on the boat.

Seasonal Service Demands

Marine shops face extreme seasonal workload swings. Spring commissioning and fall winterization create concentrated demand for diagnostic services. Having a tool that covers every manufacturer walking through your door means you can say yes to every job during your busiest months -- instead of turning away boats because you do not have the right brand-specific tool.

Who Needs Jaltest Marine Diagnostics

Marine Repair Shops

Independent marine repair shops are the primary audience for Jaltest marine diagnostics. If you service multiple brands -- and nearly every marine shop does -- you face the same problem that independent truck shops faced 15 years ago: a different proprietary tool for every manufacturer. Jaltest consolidates that toolbox into one platform covering 86 marine brands. The return on investment is straightforward. Instead of purchasing Mercury diagnostic system, Yamaha diagnostic system, Volvo Penta VODIA, and Cummins INSITE separately, you purchase one Jaltest marine kit that covers all of them.

Marinas and Full-Service Boatyards

Marinas that offer service departments benefit from Jaltest breadth of coverage. Your slip holders bring in every brand imaginable. With Jaltest, your service technicians can diagnose and repair any supported vessel without turning customers away or sending them to a brand-specific dealer. This keeps revenue in your marina and builds customer loyalty.

Commercial Vessel Operators

Commercial fishing fleets, charter operations, ferry services, towing companies, and offshore support vessel operators need diagnostic capability to minimize vessel downtime. When a boat cannot run, it cannot earn. Having Jaltest aboard or at your shore-side maintenance facility means your crew or mechanics can diagnose issues immediately instead of waiting for a dealer technician to become available -- which in remote ports can mean days of lost revenue.

Mobile Marine Technicians

Mobile marine service is a growing segment. Jaltest runs on a laptop that fits in your service truck or van. Drive to the dock, connect to the vessel, diagnose and repair on site. The portable form factor and broad manufacturer coverage make Jaltest the ideal tool for mobile marine technicians who never know what brand they will encounter at the next service call.

Boatyards and Refit Facilities

Yards that perform engine repowers, major refits, and pre-purchase surveys need deep diagnostic capability. Jaltest provides the ECU data access required for repower verification, the live data monitoring needed for sea trial diagnostics, and the fault code history that buyers want to see in a pre-purchase survey report.

What Is Included in a Jaltest Marine Diagnostic Kit

• Jaltest Marine Software License -- full marine module covering outboard, inboard, and watercraft diagnostics
• Jaltest Data-Link (VCI) -- the diagnostic interface hardware that connects your laptop to the vessel diagnostic port
• Marine Cable Set -- OEM-style connectors for marine engine diagnostic ports across all supported manufacturers
• Carrying Case -- heavy-duty protective case for dockside and on-board use
• First Year of Software Updates -- three updates per year with new coverage and features

Complete laptop kits are also available if you need the full turnkey package. See our Complete Diagnostic Laptop Kits for pre-configured systems ready to diagnose out of the box.

Why Marine Shops Choose Diesel Truck Diagnostic Tools

We have been an authorized Jaltest/Cojali dealer since 2016. Our team includes trained staff who understand marine applications -- not just truck diagnostics applied to boats. When you call 800-217-0063, you reach someone who can help you navigate a Volvo Penta IPS diagnostic procedure, troubleshoot a Cummins QSB marine fault code, or configure Jaltest for a multi-engine commercial vessel.

• Free ground shipping on every order -- no minimum, no exceptions
• Full manufacturer warranty on all Jaltest hardware and software
• Live trained-staff support -- call 800-217-0063 during business hours or email anytime
• 30-day satisfaction guarantee -- if Jaltest does not meet your needs, return it
• Financing available for shops that want to spread the investment

Get Started with Marine Diagnostics

Browse the marine diagnostic kits below or call 800-217-0063 to speak with a trained staff about your specific coverage needs. Not sure whether you need the marine module alone or a multi-industry bundle? We will help you figure that out -- no pressure, no upselling. Email us at support@dieseltruckdiagnostictools.com if you prefer to start the conversation in writing.

You can also explore our marine subcategories for detailed coverage by engine type:

• Outboard Engine Diagnostics -- 14+ manufacturers
• Inboard Engine Diagnostics -- 34+ manufacturers
• Watercraft / Jet Ski Diagnostics -- BRP/Sea-Doo, Kawasaki, Yamaha, and more