Code Map

DTC Tech Guides

Bay-ready · not a parts cannon

Paste DTCs.
Get the bay strategy.

Topology map, ordered diagnostic steps, and a tools checklist — built for indie shops and DIY techs who already know how to wrench. Free to use in the browser. Always verify everything against OEM service information and TSBs for the VIN.

Open Code Map Try P0300 + P0171 demo
9,533 Generic OBD-II codes
2,911+ Manufacturer-specific
8 Full strategy packs
33 Makes in mfr index

How Code Map works

  1. 1

    Vehicle + codes

    Year / make / model, then paste P0300, P0171 or any P/B/C/U from the scan.

  2. 2

    Strategy pack

    System topology, ordered tests, tools by step, and stop / go / verify notes.

  3. 3

    Verify with OEM

    Use the map as your plan, then confirm pinouts, torque, and TSBs in manufacturer info.

How DTC strategy thinking works

A diagnostic trouble code is a symptom pointer, not a parts order. Random misfire (P0300) next to system too lean (P0171) is a classic example: chasing coils and plugs while the engine is starved of fuel (or flooded with unmetered air) wastes hours. Code Map’s packs push sequence — confirm the air/fuel and vacuum story before you condemn ignition components — and show the related system on a topology sketch so apprentices see why step two exists.

Network and “messenger” codes need the same discipline. U0100 (lost communication with the ECM/PCM) is often power, ground, or bus integrity — not a new computer. P0700 tells you the TCM stored something; the useful work is reading the transmission codes and freeze frame, not guessing a rebuild. Strategy packs encode that habit so the bay starts in the right system.

OEM / TSB disclaimer: Code Map is educational. It is not a substitute for OEM service information, wiring diagrams, calibration files, or technical service bulletins tied to your VIN. Campaigns, software updates, and make-specific test values override any generic pack. If a step conflicts with the manufacturer procedure, follow OEM.

Strategy packs live now

Any other catalog code still gets a definition + generic diagnostic workflow. Enhanced P1xxx codes show make-specific hits when you pick a make.

Built for shops and DIY — with clear limits

Indie bays need speed without skipping fundamentals. DIY owners with a real scanner need the same ordered thinking forums often skip. Code Map is that second screen: paste codes, get a plan, then do the work with the right manuals open. Read more on About, how we handle data on Privacy, or send bay notes via Contact.

Ready for the bay?

Open Code Map

Educational tool · always verify with OEM/TSB for the VIN.