Follow the engine's guided workflow — or jump straight to the tool you need.
Use any scan tool that outputs SPN/FMI, OBD-II, or OEM dash codes. Type the code directly into the diagnostic engine, paste a screenshot, or describe the fault in plain language. The engine identifies the fault and begins the diagnostic sequence.
The FSM diagnostic engine walks you through a structured sequence of physical tests — voltage checks, pressure tests, visual inspections, and component verifications. Each step is based on real OEM diagnostic logic, not guesswork.
After each test, report what you found. The engine uses your results to narrow down the root cause, skipping irrelevant tests and focusing on what matters. The more accurately you report, the faster you reach a diagnosis.
Once the engine has enough data, it delivers a root cause determination and a prioritized repair plan — starting with the cheapest, most likely fix first. No unnecessary parts. No wasted labor.
Use the Repair Summary Builder to generate a formatted, professional repair summary from your technician notes. Print it, email it to the customer, or save it to your account. Supports typed notes or photo upload with AI OCR. Available on all paid plans.
Every completed session is saved to your account history. Reference past diagnoses, track recurring faults on a vehicle, or use saved sessions to build institutional knowledge for your shop.
Attach a photo of your scanner screen, wiring diagram, connector, or VIN label. DieselVision™ — AI Diesel Tech's advanced photo-accuracy system — runs multi-pass vision analysis, extracts fault codes, VIN, pin assignments, and live data readings, then scores each value for confidence before sending it to the diagnostic engine.
This includes:
Every paid plan includes full access to Technician Chat™ and the Repair Summary Builder.
AI Diesel Tech's instant-answer assistant for torque specs, sensor locations, fluid capacities, firing orders, and quick mechanical questions — no full diagnostic session needed.
Generate professional repair summaries from your notes in seconds. Supports typed input or photo upload with AI-powered OCR. Print or email directly. Available on all paid plans.
AI Diesel Tech's advanced photo-accuracy system for technicians.
DieselVision™ enhances technician-uploaded photos using multi-pass vision analysis, glare reduction, OCR enhancement, and confidence scoring. It reads scanner screens, wiring diagrams, connectors, sensors, part numbers, and VIN plates with unmatched clarity — giving technicians cleaner, safer, more accurate diagnostics.
DieselVision™ VIN Photo — tap the VIN Photo button on the Diagnose intake screen to photograph any VIN label. DieselVision™ extracts all 17 characters with AI-powered OCR, applies glare reduction and orientation correction, scores confidence green/amber/red, and auto-fills vehicle year, make, model, and engine platform instantly. Works on cab VIN plates, door jamb labels, and frame-mounted tags.
TIER 1
Hierarchical FSM — Top-Level Router
Deterministic state machine: INITIAL_INTAKE → CONTEXT_RESOLUTION → SUBSYSTEM_SELECTION
TIER 2
Subsystem FSMs — DPF / SCR / NOx / Turbo / Fuel / Electrical / Aftertreatment
Per-subsystem state machines: INTAKE → SENSOR_VALIDATION → ACTUATOR_TESTS → FLOW_PRESSURE_CHECKS → PLAUSIBILITY_CHECKS → VERIFICATION
TIER 3
Micro-FSMs — Precondition-gated test sequences
Each test: PENDING → PRECONDITION_CHECK → EXECUTING → AWAITING_RESULT → PASS / FAIL / INCONCLUSIVE
Gravity-scored root cause candidates. Every technician input, sensor reading, and photo analysis updates candidate scores in real time.
Detects causal chains across subsystems. Prevents replacing a DPF before fixing the upstream turbo underboost that caused it.
Evidence-gated repair plans. Only generates a plan when all required evidence gates are satisfied and a clear root cause is confirmed.
Trend analysis on live sensor data. Detects degrading DPF pressure, declining SCR efficiency, and erratic fuel rail readings before failure.
Photo and voice input. Analyzes uploaded photos for soot loading, connector corrosion, and oil traces. Extracts evidence from plain-language descriptions.
Adapts output to technician skill level. Beginners get detailed explanations; experts get dense, fast, technical output with raw FSM state.
Structured verification after repair. Confirms the fault is resolved before closing the session — prevents comebacks and incomplete repairs.
Mandatory ≤5Ω ground continuity check before any sensor resistance or signal test. Eliminates false sensor failures from bad grounds.