Search for TSBs. Has your car been recalled? Is there a software update for the transmission shudder that the dealer never told you about?

If you are a mobile mechanic, calculate the labor hours for three jobs you have next week. Compare the Haynes Pro time to your actual speed. Adjust your pricing.

Input the exact OBD-II code your car is throwing. Follow the diagnostic flow chart. Order the specific part it recommends (not just a guess).

| Feature | Haynes Pro (Trial) | AllDATA DIY | Mitchell1 DIY | ChiltonDIY | | :--- | :--- | :--- | :--- | :--- | | | 7 Days | None (pay upfront) | None (pay upfront) | 7 Days | | Wiring Diagrams | Yes (OEM color) | Yes (OEM) | Yes (Detailed) | Limited | | Labor Times | Yes (Pro feature) | Yes | Yes (Gold Standard) | No | | TSB Updates | Yes | Yes | Yes | Rare | | Best For | European/Asian imports | Domestic US | Professional billing | Beginners |