Top 12 Diesel Technician Skills to Put on Your Resume
The diesel world keeps shifting. New engines, cleaner emissions, smarter trucks. Employers want technicians who can diagnose fast, repair right, and communicate clearly. A sharp resume helps, but the skills behind it matter more. Build them, show them, and doors open.
Diesel Technician Skills
- Diagnostics
- Hydraulics
- Pneumatics
- Cummins INSITE
- Detroit Diesel Diagnostic Link
- Welding
- ASE Certification
- Electrical Systems
- HVAC Systems
- Allison Transmission
- Preventive Maintenance
- DPF Systems
1. Diagnostics
Diagnostics means finding the fault without guesswork. Pulling codes, tracing circuits, reading live data, and proving the failure with tests so repairs are targeted and verifiable.
Why It's Important
Accurate diagnostics cuts downtime, prevents parts cannon repairs, and protects engines from secondary damage. Faster answers, fewer comebacks.
How to Improve Diagnostics Skills
Master the process: Verify the complaint, check basics first, pull codes and freeze-frame, analyze live data, test, confirm, then repair. Document everything.
Use the right tools: RP1210/J2534-compatible adapter, reliable scan software, DVOM, amp clamp, oscilloscope, smoke machine, pressure/vacuum gauges, infrared thermometer.
Know the systems: J1939/J1708 networks, sensor operation, actuator control, fuel and air management, aftertreatment logic.
Leverage service info: OEM procedures, wiring diagrams, fault trees, specifications. No shortcuts on data.
Practice pattern recognition: Compare known-good waveforms and data PIDs. Build your own library of captures.
Keep learning: Take OEM and industry training, shadow specialists, trade notes with other techs.
How to Display Diagnostics Skills on Your Resume
2. Hydraulics
Hydraulics uses pressurized fluid to transmit power. Pumps, valves, cylinders, motors—lifting, steering, braking, stabilizing. Common on heavy trucks and equipment tied to diesel power.
Why It's Important
Critical systems rely on hydraulics. Poor maintenance means leaks, heat, slow operation, and component failure. Good hydraulics keep machines strong and safe.
How to Improve Hydraulics Skills
Control contamination: Clean assembly practices, proper filtration, routine fluid sampling, and tight reservoir management. Dirt is the main killer.
Test with numbers: Flow meter, pressure gauges, and temperature checks to validate pump output, relief settings, and heat load.
Use correct fluids: Viscosity and additive package matched to climate and component specs. Don’t mix fluids unless approved.
Inspect routing: Hose abrasion, bend radius, clamp placement, and fitting torque. Fix weeps before they become gushers.
Upgrade where it counts: Better filtration, condition monitoring, and modern valve technology can extend life and improve control.
Train and document: Procedures, torque specs, flushing methods, and failure analysis notes. Leave a trail others can follow.
How to Display Hydraulics Skills on Your Resume
3. Pneumatics
Pneumatics uses compressed air to power and control systems. Air brakes, suspension, accessories, and controls across trucks and equipment—not inside the engine, but essential to the vehicle.
Why It's Important
Safe braking, consistent actuation, and reliable control depend on clean, dry, leak-free air. Small leaks turn into big problems fast.
How to Improve Pneumatics Skills
Eliminate leaks: Soapy water tests, ultrasonic detection, proper ferrules and fittings, and correct torque. Fix the hiss.
Dry the air: Maintain compressors, governors, air dryers, and desiccant. Drain tanks. Water wrecks valves and lines.
Protect components: Use proper FRLs where required. Keep filters clean and regulate pressure to spec.
Test performance: Pressure decay tests, response timing, and system recovery checks to verify health.
Install right: Correct hose material and rating, bend radius, abrasion protection, and clear labeling for diagnostics later.
How to Display Pneumatics Skills on Your Resume
4. Cummins INSITE
Cummins INSITE is OEM diagnostic software for Cummins engines. Connects to the ECM, reads faults and live data, performs tests, updates calibrations, and documents repairs.
Why It's Important
For shops servicing Cummins power, INSITE is the language the engine speaks. Faster troubleshooting, proper parameter management, and accurate reporting.
How to Improve Cummins INSITE Skills
Stay current: Keep software and calibration files updated. Know feature changes and new test routines.
Use proper hardware: A dependable laptop and an approved RP1210 adapter ensure stable communications on J1939/J1708.
Know the data: Trend key PIDs, log recordings under load, and compare to known-good values. Data reveals drift.
Follow service info: QuickServe procedures, wiring, and specs guide successful tests and calibrations.
Build templates: Standardize work orders, reports, and post-repair validations for consistency and speed.
How to Display Cummins INSITE Skills on Your Resume
5. Detroit Diesel Diagnostic Link
Detroit Diesel Diagnostic Link (DDDL) communicates with Detroit ECMs to read/clear faults, command tests, adjust parameters, and perform programming.
Why It's Important
When Detroit powertrains roll in, DDDL is the key. It speeds up root-cause analysis and ensures ECM settings match the application.
How to Improve Detroit Diesel Diagnostic Link Skills
Update routinely: Software, drivers, and firmware need to match current engines and controllers.
Practice on-platform: Use demo modes and non-critical units to explore features before high-stakes jobs.
Validate changes: Record baseline data, make one change at a time, log results, and revert if needed.
Harden your setup: Quality cables, stable power supply, and proper battery support prevent bricking during flashes.
Compare vehicles: Cross-check a healthy unit’s data and parameters to spot outliers quickly.
How to Display Detroit Diesel Diagnostic Link Skills on Your Resume
6. Welding
Welding joins metals through heat and fusion. On diesel equipment, it means brackets, frames, exhausts, mounts, and repair of worn or cracked components.
Why It's Important
Strong welds restore structure and function. Poor welds fail under load and vibration. The difference shows up on the road and in the yard.
How to Improve Welding Skills
Learn multiple processes: GMAW (MIG) for speed, GTAW (TIG) for precision, SMAW (stick) for field work. Choose based on material and access.
Prep like it matters: Clean metal, proper bevels, correct fit-up, and solid fixturing reduce defects and distortion.
Match filler and heat: Use the right wire/rod and parameters for steel, stainless, aluminum, and cast iron. Preheat and postheat when required.
Inspect your work: Visual checks, dye penetrant where needed, and torque/load tests after installation.
Chase certs: Training and certifications (such as AWS structural codes) sharpen technique and credibility.
Safety always: PPE, ventilation, fire watch, cylinder handling, and battery disconnects on vehicles.
How to Display Welding Skills on Your Resume
7. ASE Certification
ASE Certification signals validated skill. For diesel techs, that can include Light Vehicle Diesel (A9) and, for medium/heavy trucks, the T-series: T2 Diesel Engines, T6 Electrical/Electronic Systems, T7 HVAC, and T8 Preventive Maintenance Inspection.
Why It's Important
It builds trust. Employers, fleets, and customers see a standard met—knowledge tested, experience proven.
How to Improve ASE Certification Skills
Target the right exams: Pick A9 for light-duty diesel; add T2, T6, T7, T8 for heavy-duty work.
Study with intent: Use current task lists, focus on weak areas, and simulate test timing.
Stack experience: Daily hands-on work cements concepts. Seek jobs that cover the test domains.
Refresh regularly: Recertify on schedule, track changes in technology, and keep notes that evolve with you.
Build a study circle: Compare notes, trade questions, and teach others to clarify your own understanding.
How to Display ASE Certification Skills on Your Resume
8. Electrical Systems
Electrical systems cover starting, charging, lighting, controls, sensors, and networks. Batteries, alternators, starters, wiring, grounds, modules, and CAN/J1939 communication.
Why It's Important
Engines won’t start, modules misbehave, and data turns noisy when electrical health slips. Solid diagnostics here saves hours everywhere else.
How to Improve Electrical Systems Skills
Test under load: Voltage drop tests beat visual checks. Load batteries properly and measure alternator ripple.
Use an oscilloscope: Cranking waveforms, sensor signals, injector and coil current ramps—see what a meter can’t.
Repair the right way: Quality crimps, sealed heat-shrink, loom protection, grommets, and proper routing to avoid chafe.
Chase grounds: Clean, tight, corrosion-protected ground paths. Add supplemental grounds when needed.
Network savvy: Identify backbone wiring, termination resistors, and bus health. Fix one stub and the whole network calms down.
Document findings: Capture before/after data and photos. Future you will thank present you.
How to Display Electrical Systems Skills on Your Resume
9. HVAC Systems
HVAC controls temperature, airflow, and humidity in the cab. Compressors, condensers, evaporators, orifice devices/expansion valves, blend doors, and controls—usually R-134a on heavy-duty, with proper oils and seals.
Why It's Important
Comfort keeps operators sharp. Proper HVAC also protects electronics and defogs glass for safety.
How to Improve HVAC Systems Skills
Service by the book: Recover, evacuate, weigh in charge, and verify with pressures and outlet temps. Guessing the charge invites callbacks.
Find leaks precisely: UV dye, electronic detectors, nitrogen pressure tests, and mindful inspection of common rub points.
Mind the airflow: Clean condensers, straight fins, strong condenser fan operation, and cabin filters where equipped.
Use the right oil: Match oil type and quantity to compressor design and component replacement.
Know regulations: Proper refrigerant handling practices and required certifications keep you compliant.
How to Display HVAC Systems Skills on Your Resume
10. Allison Transmission
Allison manufactures automatic transmissions for medium and heavy-duty vehicles. Widely used across fleets, municipal trucks, buses, and off-road equipment.
Why It's Important
These transmissions are everywhere. Understanding diagnostics, fluid specs, and adaptation behavior keeps vehicles shifting cleanly and lasting longer.
How to Improve Allison Transmission Skills
Follow the maintenance map: Service intervals by vocation, filter changes, and sump checks. Use approved fluid (current spec includes TES 668; older units may list TES 295).
Read the data: Pull TCM codes, monitor clutch apply pressures and temps, and review shift adapt values.
Keep it cool: Inspect coolers, lines, and heat exchangers. Heat kills transmissions quietly.
Verify wiring: Look for harness chafe, loose connectors, and poor grounds. Transmission faults often start electrical.
Perform relearns correctly: After repairs, complete proper adaptation procedures and confirm shift quality on a road test.
How to Display Allison Transmission Skills on Your Resume
11. Preventive Maintenance
Preventive maintenance is the rhythm of inspection and service that prevents breakdowns—fluids, filters, adjustments, torques, and checks done before parts beg for help.
Why It's Important
It cuts unplanned downtime, extends component life, and keeps fuel economy and emissions where they should be.
How to Improve Preventive Maintenance Skills
Standardize inspections: Checklist-based PMs with measurements—brake lining remaining, DEF quality, coolant pH/SCA, battery conductance, tire pressures, torque audits.
Use oil and fluid analysis: Track wear metals, soot, fuel dilution, viscosity, and coolant contamination to spot trouble early.
Mind the drivetrain: U-joints, slip yokes, driveline angles, yoke spline lubrication, and seal checks.
Watch the fuel system: Water separators, filter intervals, leak checks, and injector balance tests when symptoms appear.
Log aftertreatment health: Regen history, differential pressure trends, and temperature sensor plausibility during PM.
Track everything: A maintenance system for work orders, parts usage, and interval forecasting keeps fleets humming.
How to Display Preventive Maintenance Skills on Your Resume
12. DPF Systems
Diesel Particulate Filter (DPF) systems trap soot in the exhaust and burn it off during regeneration. They work alongside the DOC and, in many setups, the SCR system to meet emissions standards.
Why It's Important
Healthy DPF operation keeps engines compliant and efficient. Neglect leads to backpressure, forced regens, limp modes, and expensive component swaps.
How to Improve DPF Systems Skills
Measure, don’t assume: Verify differential pressure, temperature sensor plausibility, and regen completion rates before replacing parts.
Promote clean combustion: Fix air and fuel faults that create excess soot—boost leaks, EGR issues, injector problems, and low compression.
Regenerate correctly: Perform parked/forced regens only under proper conditions with battery support, and confirm post-regen pressures.
Service the hardware: Clean ash at the correct intervals, check for substrate damage, and ensure gaskets and clamps seal tight.
Validate dosing systems: If equipped with SCR, confirm DEF quality, dosing accuracy, and NOx sensor performance to prevent cascading faults.
Update software: Calibration changes often improve regen logic and sensor diagnostics. Keep ECMs current.
How to Display DPF Systems Skills on Your Resume
