JOHN DEERE 17 HP COMM MOW Service Manual

Overview and safety considerations

The JOHN DEERE 17 HP COMM MOW service manual provides essential guidance for the inspection, maintenance, troubleshooting, and repair of the commercial mower system. This section introduces the purpose of the manual, along with the key safety practices and vocabulary that technicians use when servicing the equipment. It is designed to help skilled technicians understand assembly relationships, service intervals, and common fault modes to keep the mower operating at peak performance. Clear procedural steps and torque values, when provided, should be followed precisely to avoid unintended damage and to preserve machine integrity. The information here sets the foundation for effective, repeatable maintenance work that supports productivity and safety on the job site.

Safety rises to the forefront in every operation involving commercial mowing gear. Proper protective equipment, including eye protection, hearing protection, gloves, and sturdy footwear, is essential before performing any service task. Always disconnect the power source and secure the machine to prevent unexpected startup during maintenance. Engage lockout/tagout procedures where applicable and ensure the area is free of bystanders. Adhering to manufacturer warnings and local safety regulations minimizes the risk of injury from moving parts, pressurized systems, or hot surfaces. When in doubt, pause the task and consult the manual or qualified service personnel to verify the correct procedure before proceeding.

Symbols and terminology used throughout the documentation convey critical information quickly and uniformly. Common symbols indicate electrical hazards, sharp edges, rotating components, and required personal protective equipment. Terminology covers measurement units, tolerances, and reference designations for parts and fasteners. A clear understanding of these symbols and terms helps technicians interpret service procedures accurately, ensuring that steps are executed with the correct orientation and torque, and that replacement parts match the original specifications. Consistent use of symbols and defined terms reduces ambiguity and supports safe, efficient maintenance work across different service tasks.

Equipment identification and specifications

The JOHN DEERE 17 HP COMM MOW is a compact commercial mowing unit designed for reliable field performance in professional landscaping and maintenance operations. Accurate identification of the machine model, serial number, and production year is essential for ordering the correct service parts and ensuring proper replacement of components. Inspect the data plate located on the frame near the engine compartment or beneath the operator platform to confirm the exact model designation and build range. Record any label identifiers, including the machine's serial code, to facilitate future maintenance logs and service advisories. When identifying the equipment, verify that the control layout, deck dimensions, and hitch configuration match the documented specifications for the particular production run you are servicing.

Technical specifications and capacities for this machine provide the foundation for safe and effective maintenance procedures. The 17 HP engine delivers a balance of power and efficiency suitable for mid- to heavy-duty mowing tasks, with a defined horsepower rating, displacement, and fuel system arrangement consistent with the manufacturer’s performance curves. Pay close attention to oil capacity, recommended lubricant grades, coolant type, and capacity, as well as hydraulic system pressure and flow where applicable. The cutting deck width, blade count, transport dimensions, weight, and tire or tread specifications are critical when calculating site limitations and load handling. Always consult the service sheet for your specific serial range to confirm any variation in capacities that may affect maintenance intervals or replacement part numbers.

Tooling and spare parts nomenclature covers the essential hand tools, test equipment, and common consumables required to service the JOHN DEERE 17 HP COMM MOW. Identify standard tooling such as torque wrenches, feeler gauges, troubleshooting scanners, and zerk or grease fittings used throughout routine maintenance. Spare parts nomenclature includes filters (oil, fuel, air), spark plugs or glow plugs if applicable, belts, PTO components, driveline couplers, blades, and deck spindles. Proper documentation of part numbers, manufacturer cross-refs, and interchangeability within the same family ensures rapid part replacement and minimizes downtime. Maintain an organized storage system for small components like gaskets, seals, fasteners, and o-rings, labeling each bin with the corresponding assembly area to streamline service workflows.

Pre operation inspection is the first and one of the most critical steps before starting the JOHN DEERE 17 HP COMM MOW. Begin by checking the overall condition of the mower, looking for any loose fasteners, damaged guards, or signs of wear on the cutting deck. Verify that the engine oil level is within the recommended range using the dipstick, and inspect engine coolant level if applicable. Examine the air cleaner for excessive dirt or damage and replace or clean it as needed to prevent contaminants from entering the engine. Ensure that all safety devices, such as blade brake or engagement mechanisms and seat switch, are functioning properly. Finally, inspect the fuel system for leaks and confirm that the fuel cap seals correctly to prevent evaporation and contamination.

Lubrication points and intervals cover essential bearings, pivots, and moving linkages that keep the machine operating smoothly. Regularly grease the front wheel hubs, output shaft bearings, and pulley bearings according to the manufacturer’s recommended intervals, paying attention to any grease fittings on hard-to-reach areas. Check and lubricate the deck height adjustment mechanism to ensure smooth operation and precise cutting heights. For hydraulic and electric components, use the specified lubricant type or follow the manual’s guidance on oil changes and lubrication frequency. Document each lubrication, noting the date and mileage or hours to maintain an accurate maintenance history.

Filter and fluid checks focus on maintaining clean intake and proper fluid levels to prevent premature wear and overheating. Inspect the engine oil filter and replace it at the intervals indicated by Deere’s maintenance schedule or whenever a high level of contaminants is detected during routine changes. Check the fuel filter for signs of contamination or clogging and replace as necessary to maintain steady fuel flow. Inspect transmission and hydraulic filters for cleanliness and replace them according to the service schedule to preserve hydraulic efficiency. Finally, verify coolant, windshield washer if equipped, and other essential fluids remain at proper levels and free of leaks, ensuring optimal cooling and lubrication during operation.

Engine and starting system service

The JOHN DEERE 17 HP COMM MOW engine requires regular inspection and maintenance to ensure reliable starting and efficient operation. Begin with a careful visual assessment of the engine area, checking for signs of fuel leaks, loose fasteners, cracked hoses, and evidence of overheating. Ensure the mower is on a level surface, the parking brake is engaged, and the spark plug wire is disconnected when performing inspections to prevent accidental starting. When inspecting fuel lines, look for brittleness, swelling, or cracking, and replace any damaged hoses with OEM components to maintain fuel system integrity. Maintain clean, dry condition around the air intake to prevent dirt intrusion that could affect starting and performance.

Fuel system inspection and maintenance involves testing the fuel delivery and checking for contaminants in the fuel. Start by confirming the fuel cap seals properly and there is no vapor lock risk due to a faulty vent. Inspect the fuel filter for sediment or debris and replace it if found dirty or clogged, following the manufacturer’s torque specifications for securing fittings. Drain any water or sediment from the fuel tank if the design includes a drain, and inspect the fuel line for kinks that could restrict flow. After servicing, prime the system as required and verify there are no fuel leaks around the connections. When performing maintenance on the carburetor or fuel pump, use tools that won’t introduce foreign materials into passages, and reassemble with correct gaskets and seals to prevent air leaks and poor starting.

Air filter inspection and replacement is essential for preventing dirt ingestion that can accelerate wear and cause hard starting. Remove the air cleaner cover carefully without letting dirt fall into the intake, then inspect the element for tears, oil saturation, or excessive buildup. If the filter is oily or saturated with fine dust, replace it with a new OEM filter and ensure the seals and grommets seat correctly to prevent unfiltered air from bypassing the filter. When reassembling, confirm the air intake duct is free of cracks and secure all clamps and fasteners to maintain a proper seal. Document any conditions observed during inspection, as persistent dirt intrusion can indicate a broader intake or sealing problem that requires further diagnosis.

Ignition system and starting procedure require attention to spark quality and proper timing for dependable starts. Inspect the spark plug(s) for fouling, electrode wear, and proper gap setting as specified by the engine documentation; replace plugs that show signs of heavy fouling or damage. Check the ignition coil and wires for cracks, insulation wear, and secure connections, replacing any damaged components to maintain a reliable spark. Verify that the starting procedure follows the correct sequence for priming, if applicable, and ensure the battery or recharge system provides adequate voltage during cranking. When performing starting tests, use safe starting practices, keep hands and clothing clear of moving parts, and observe any abnormal noises or misfires that may indicate underlying mechanical issues needing service beyond routine maintenance.

Overall, routine service of the engine and starting system on the JOHN DEERE 17 HP COMM MOW should focus on ensuring clean air intake, reliable fuel delivery, and a strong ignition spark. Document maintenance actions with dates and part numbers to establish a clear service history and plan future intervals based on operating hours and environmental conditions. By following these procedures, operators can achieve smoother starting, improved performance, and longer engine life, even under demanding mowing schedules.

Some additional reminders include verifying that all safety shields and guards are in place before operation, wiping away any spilled fuel or oil to prevent slip hazards, and disposing of used filters and old parts according to local regulations. Regular calibration checks for any starting aids or choke mechanisms should be performed after maintenance to confirm correct operation. If you encounter recurring starting difficulties, consider consulting the manufacturer’s service bulletin or contacting an authorized service center to diagnose potential combustion or compression issues that may require expert attention.

Transmission type and maintenance: The JOHN DEERE 17 HP COMM MOW typically uses a hydrostatic or gear-driven transmission depending on the model configuration. Regular maintenance begins with checking the transmission fluid level and confirming the fluid type specified in the manufacturer’s guidelines. Use only the recommended lubricant grade and viscosity, and inspect for contamination or moisture, which can indicate seal leaks or internal wear. Replace filters as required by service intervals and drain-and-fill to the correct capacity, ensuring the system is purged of air after resealing. Periodic inspection should include checking transmission mounting hardware for looseness, inspecting cooling passages if applicable, and listening for unusual noises that may indicate bearing wear or internal rotor issues in hydrostatic units. Maintain clean ventilation around the transmission to prevent overheating during operation, and avoid aggressive operation after cold starts until the system reaches normal operating temperature. If a loss of drive or slipping occurs, perform a diagnostic test to determine whether the issue is hydraulic pressure, linkage adjustment, or belt interaction, following the manufacturer’s troubleshooting flowchart and safety precautions. Always disconnect the battery and disable the ignition before performing internal checks or seal replacement to prevent accidental engine engagement.

Drive belts and pulleys inspection: Inspect all drive belts for cracks, fraying, glazing, or missing ribs, and measure belt tension according to the service manual specifications. Replace worn belts promptly to maintain proper drive ratios and to prevent slipping that can overstress clutches and bearings. Examine pulleys for grooves, misalignment, or wobble; rotate pulleys by hand to detect roughness or binding that could indicate bearing wear. When adjusting belt tension, follow the precise procedure for the model, ensuring the belt is seated correctly in all grooves and that alignment marks are matched during reassembly. After maintenance, recheck belt tension with the machine on a level surface and with the deck engaged in a safe mode, verifying that belts track true and do not rub against guards or housings. Use only OEM belts or equivalents recommended by Deere, and avoid mixing belt types or brands, which can alter torque characteristics and shorten component life. If a belt shows persistent slipping under load after proper tensioning, investigate the drive pulleys for damage or misalignment and inspect associated clutches or PTO linkage for binding or wear.

Hydraulic system overview and checks: The hydraulic system provides engine-powered grounding for drive and deck functions, and routine checks should include inspecting for leaks at lines, fittings, and hydraulic cylinders. Check hydraulic fluid level with the machine on a level surface and the reservoir at the correct temperature; look for signs of contamination such as particulates or water, which can indicate improper filtration or seal failures. Replace hydraulic filters at the manufacturer-recommended intervals and when fluid shows contamination, using compatible fluids and a clean work environment to prevent further contamination. Inspect hydraulic hoses for cracking, swelling, or abrasion, and replace any hose that shows signs of wear or exposed braid. Purge air from the hydraulic system after servicing by cycling through the control levers several times with the engine off, then recheck for smooth operation and correct response times. Monitor temperature during heavy use to prevent overheating, and ensure cooling fins and radiators are clean and unobstructed to maintain optimal hydraulic performance. If system pressure readings fall outside specification, consult the service manual for the correct diagnostic procedure, as variations can indicate worn seals, failed compensators, or pump wear.

Electrical system diagnostics and repair

Battery care and charging The performance and longevity of the electrical system on the JOHN DEERE 17 HP COMM MOW depend on proper battery care and a reliable charging circuit. Begin by inspecting the battery case for swelling, cracks, or corrosion on terminals, and ensure the battery is securely mounted to prevent movement that can loosen connections. Clean any corrosion with a solution of baking soda and water, then rinse and dry thoroughly before applying a light layer of dielectric grease to protect terminals from future oxidation. When testing, use a calibrated digital multimeter to confirm resting voltage, which should typically be within the manufacturer’s specified range; if the voltage is significantly low, charge the battery with an appropriate charger at a controlled rate, avoiding high-helocity charging that can damage internal plates. After charging, perform a load test or cranking test to verify the battery’s ability to deliver sufficient amperage under load; if the voltage collapses quickly, the cell plates may be compromised and the battery should be replaced. Regularly check electrolyte levels in maintenance-free variants as recommended by Deere, and ensure electrolyte levels remain within the indicated limits to prevent plate sulfation and reduced capacity over time. Finally, verify that the charging system, including the alternator or stator, is functioning properly by measuring charging voltage with the engine running at a governed RPM; typical readings should fall within the OEM specification, with fluctuations indicating a potential regulator problem or loose wiring. Wiring harness inspection A comprehensive inspection of the wiring harness is essential to preventing intermittent electrical faults that can affect starting, ignition, and accessory operation. Visually inspect all harnesses for cracked insulation, pinched wires, or signs of heat damage near the engine, exhaust components, and under the dash; pay special attention to weatherproof connectors that may corrode when exposed to moisture. Disconnect and test involved connectors for continuity and proper resistance using a digital multimeter, ensuring there are no short circuits or open circuits in circuit branches that control lights, gauges, and safety interlocks. Check ground straps and battery negative cables for tightness and clean connections; poor grounding is a common source of oscillating readings and erratic instrument behavior. Inspect the ignition switch, PTO switch, and safety interlock circuits for proper operation; a faulty switch can prevent starting or cause the engine to shut down unexpectedly. Re-seat all connectors with dielectric grease to improve contact resistance and reduce future corrosion, and replace any damaged harness sections or connectors with OEM-recommended parts to preserve electrical integrity and safety. Troubleshooting common electrical faults Common electrical faults on the JOHN DEERE 17 HP COMM MOW include failure to start, intermittent starter operation, dim or flickering gauges, and non-functioning accessories such as lights or PTO indicators. Begin diagnostic work by confirming the battery is fully charged and that all main fuses and circuit breakers are intact; a blown fuse or tripped breaker can emulate more complex failures. If the engine cranks slowly or fails to crank, test for proper battery voltage at the starter solenoid while the key is in the start position; a stiffened or weak signal indicates battery or starter circuit issues, whereas a robust signal with no cranking points to a faulty starter motor or a bad solenoid contact. For electrical accessories that do not function, trace each circuit from its power source through switches and fuses to the device, checking for loose connections, improper ground, or damaged conductors; replace any damaged components with OEM equivalents to maintain compatibility and safety. If warning lights or gauges display inconsistent readings, calibrate or replace the corresponding sensors and verify the instrument cluster ground path is solid; sometimes a ground loop can produce fluctuating indications. Finally, perform a comprehensive system test after repairs by running the mower at various engine speeds, engaging safety interlocks, and activating all electrical accessories to ensure stable operation and to verify that no new faults have been introduced during repair.

Safety and functional testing procedures Safety interlocks and guards verification All safety interlocks and guards must be tested to ensure proper operation before and after any maintenance. Begin by turning the ignition off and removing the key, then manually inspecting each interlock linkage for freedom of movement and unobstructed paths. Verify that the blade engagement switch engages only when the operator presence control is activated and the parking brake is released. Check that the mower blades disengage immediately when the operator presence control is released and that the PTO clutch reverts to the disengaged state. Inspect protective guards, shielding, and guards around the belt drive and cutting area for cracks, loosening fasteners, and secure mounting. If any guard is damaged or missing, replace it and retest to confirm protection, ensuring no exposed moving parts remain during operation. Document all findings and replace or repair components as necessary prior to returning the machine to service. Operating tests and performance checks Conduct a comprehensive series of operating tests to validate that the machine performs within manufacturer specifications. Start with a cold engine and verify stable idle, smooth throttle response, and consistent RPM under load. Engage the hydraulic and drive systems to confirm that forward and reverse movement is precise and free of unusual noises or vibrations. Test the cutting deck operation at multiple ground speeds, ensuring uniform blade speed and consistent cutting performance across different terrains. Listen for abnormal sounds from the engine, transmission, or PTO system, and check for overheating indicators during extended operation. Measure blind spots and ensure all warning indicators illuminate as required when faults are detected, and verify that the machine shuts down safely under fault conditions. Complete a load test by mowing a representative area and inspecting cut quality, deck level, and RPM stability throughout the cycle. Record all measurements, any deviations, and corrective actions taken to bring performance within specification. Brakes, steering, and suspension inspection Assess braking performance by applying the service brakes at various speeds and noting stopping distance, pedal feel, and rotor or drum condition. Inspect brake lines and fittings for leaks, cracks, or signs of wear, replacing any compromised components. Evaluate steering response by performing gentle and sharp steering maneuvers to confirm alignment, tracking, and lack of excessive play or binding. Check the steering linkage, tie rods, and wheel hubs for wear, looseness, or damaged components, tightening or replacing as required. Inspect the suspension system, including bushings, shocks, and springs, for wear, corrosion, or leaks, and confirm that the ride height is consistent across all wheels. Ensure that all fasteners are secure, with no missing cotter pins or safety clips, and verify that the overall chassis remains square and true after testing. Document any issues and schedule repairs before the machine returns to active duty.

Disassembly, inspection, and reassembly guides Major component removal procedures Removing major components from the JOHN DEERE 17 HP COMM MOW involves methodical steps to prevent damage and ensure accurate reassembly. Begin by disconnecting the battery and ensuring the unit is on a level, stable surface with the ignition keys removed. Label and organize fasteners as you remove them, using labeled bags or trays to keep bolts, nuts, and washers matched to their original locations. When removing the mower deck, elevate the machine safely and support the deck with appropriate stands to maintain balance and prevent accidental tipping. For the engine and transmission assemblies, disconnect ancillary lines, electrical harnesses, and mounting brackets in a logical sequence, photographing connections if needed for reference. Use the correct tools and avoid cross-threading by starting fasteners by hand before torquing to specification. Upon removal, store components in a clean, dry area to protect seals and gaskets from contamination. Wear inspection criteria and replacement guidelines Inspection criteria focus on identifying wear beyond operational tolerance and potential failures that could compromise performance. Inspect the drive belts for glazing, cracks, or missing ribs and replace if any sign of wear is detected. Check pulleys for grooves, scoring, or excessive play and ensure alignment is true to prevent belt wear or drive slip. Evaluate bearings and bushings for smooth operation without lateral play or abnormal noise; replace worn bearings promptly to avoid chain reaction damage to adjacent components. Examine gears and gear teeth for chipping, pitting, or excessive backlash; if observed, replace the affected gear set and re-check mesh alignment during reassembly. Assess seals and gaskets for seepage; replace any components showing evidence of oil or fuel leaks to preserve lubrication integrity. Document inspection results with part numbers and pothes for future maintenance cycles. Reassembly torque specifications and test checks Reassembly requires meticulous torque control to ensure proper clamping force and reliable performance. Begin by reinstalling major assemblies with new gaskets or O-rings as required, aligning dowel pins where present to ensure precise positioning. Apply manufacturer-recommended torque values to fasteners in a cross-pattern sequence to promote even clamping and avoid distortion of housings. After assembly, inspect critical clearances by measuring with a feeler gauge or digital caliper where applicable, ensuring stated tolerances are met. Conduct a functional test that includes starting the engine, verifying charging system operation, and confirming safe operation of the drive and cutting systems. Perform a test run under load to monitor for unusual vibrations, noises, or overheating, and re-check torque values if any fasteners loosen during the initial run. Finally, perform a thorough safety inspection, confirm that guards and shields are correctly installed, and verify that all safety interlocks are functioning as designed before returning the mower to service.

Troubleshooting and repair charts

Common symptoms and root causes are the foundation of efficient diagnostic work for the John Deere 17 HP commercial mowing machinery. When a symptom presents itself, begin by confirming basic operating conditions such as fuel quality, air filter cleanliness, and battery health, as these universal factors can masquerade as more complex issues. Engine performance concerns—such as hard starting, misfiring, or loss of power—often trace back to ignition timing, fuel delivery, or air intake restrictions. Electrical anomalies like no starts or intermittent stalling frequently point to loose connections, corroded terminals, or damaged fuses and relays. For cutting deck irregularities, inspect belt tension, blade sharpness, and spindle bearings, since mechanical wear cascades into vibration, uneven cuts, and heightened noise levels. Finally, overheating symptoms usually indicate cooling system interruptions, such as blocked radiators, failed thermostats, or compromised coolant flow, which require careful inspection of hoses and heat exchange passages.

Step by step diagnostic flow provides a repeatable approach to isolate issues with precision. Start with a visual and audible assessment to identify obvious faults, then proceed to a controlled functional test of the starting, charging, and ignition systems. Use a multimeter to verify voltage at key points and ensure ground paths are solid, as weak grounds can mimic multiple electrical faults. If fuel issues are suspected, perform a fuel pressure check and inspect the entire fuel system, including the fuel filter, lines, and tank venting, to rule out restrictions or contamination. For air and emissions concerns, conduct a thorough air filter inspection and confirm there is no excessive intake resistance; if present, clean or replace as required. When diagnosing the cooling system, establish proper coolant level, inspect the radiator fins for debris, and verify that the thermostat opens within specification. Throughout the process, document all measurements, correlate symptoms with service history, and prioritize safety by disconnecting power when performing electrical work and using proper lockout procedures before component service.

Parts replacement recommendations focus on selecting components with direct compatibility and proven reliability for the 17 HP commercial mower. Replace worn or damaged components with OEM-compatible parts to preserve performance and warranty integrity; avoid aftermarket substitutes that lack exact specifications. For ignition systems, install new spark plugs that meet the engine’s heat range and gap recommendations, and consider replacing worn ignition coils only if diagnostic tests indicate voltage drop or misfire patterns correlated to coil performance. Fuel system components such as filters should be replaced on a schedule aligned with runtime and operating conditions, while hoses and clamps are inspected for cracking or leaks and replaced if any signs of wear are detected. For the cooling system, priority parts include the water pump seal, radiator, and thermostat; replacing seals and gaskets during service prevents future leaks and reduces downtime. On the deck and drive train, replace worn belts, pulleys, and spindle bearings with OEM-spec parts, and keep cataloged torque specifications handy to ensure proper reassembly and balanced operation after maintenance work. Always perform a final functional test after parts replacement to verify that the issue is resolved and that the mower operates within the manufacturer’s stated parameters.

The JOHN DEERE 17 HP COMM MOW service manual appendix provides critical reference materials to ensure proper maintenance, safe operation, and reliable performance of the mower. This section consolidates torque specifications, lubricant and fluid requirements, and the warranty and service policy to support technicians in the field. Accurate torque values are essential for fasteners that affect drive, cutting, and safety systems, and correct lubricants help minimize wear, reduce heat, and extend component life. By maintaining precise specifications and documented policies, technicians can diagnose issues efficiently and perform compliant, repeatable service tasks.

Torque specification table

The torque specification table lists fastener sizes and their corresponding torque values for critical components across the JOHN DEERE 17 HP COMM MOW. When tightening crankshaft, pulley, blade spindle, deck hardware, and engine mounting hardware, it is essential to follow the exact torque figures to prevent overtightening or under-tightening, which can lead to premature failure or safety hazards. Use a calibrated torque wrench and apply clean, dry threads, with appropriate lubricants only when specified. For threaded studs and bolts that are subject to heat cycling, consider retorque procedures after initial operation to account for any relaxation or seating of the fasteners. Always verify that the fasteners are in the correct grade and thread engagement as outlined in the table to maintain warranty compliance and machine integrity.

Lubricant and fluid specifications

The manual specifies the correct lubricants and fluids required for optimal performance of the mower’s engine, transmission, hydraulics, and greases. Use manufacturer-approved oil grades and viscosities, and adhere to change intervals to protect internal components from wear and corrosion. The section details fuel requirements, such as octane rating and ethanol content, as well as coolant type and maintenance intervals for the cooling system. Proper lubrication of bearings, pivot points, and linkages reduces friction, minimizes heat buildup, and extends service life. Always inspect seals and gaskets for leaks and replace them with genuine parts to maintain fluid integrity and prevent contamination of the drive and cutting systems.

Warranty and service policy

The warranty and service policy outlines eligibility, coverage terms, and the responsibilities of both the user and the service provider. It includes constraints related to maintenance intervals, the use of approved parts, and adherence to service procedures specified by JOHN DEERE. Understanding the policy helps technicians document service events accurately, ensuring that repairs remain within warranty boundaries and that any claims are supported by proper records. The section also covers what constitutes misuse or improper maintenance and the steps required to submit a claim, including proof of purchase, service dates, and parts utilized. By following the documented policy, owners can avoid denial of warranty coverage and maintain confidence in the machine’s reliability and safety.