OBD-II Fault Code Handbook + Workshop Posters

Your check engine light is on. Now you’ll know exactly what it means – and what to check first.

The OBD-II Fault Code Handbook turns any fault code from your scanner into a clear action plan: what the code means, how serious it is, the most common causes in order, and whether it’s a job for your driveway or for a workshop.

What’s inside

✅ 120+ OBD-II fault codes explained in plain English, grouped by system (misfire, fuel, sensors, emissions, transmission, network)
✅ Severity rating for every code: OK to drive · Fix soon · Stop / tow
✅ DIY rating: Easy · Medium · Workshop – so you know before you start
✅ Most common causes first – check the cheap things before buying parts
✅ Step-by-step fix guides for the codes you’ll meet most: misfires (P0300–P0308), lean mixture (P0171/P0174), catalyst (P0420), EVAP leaks, thermostat (P0128) and EGR (P0401)
✅ The 7-step diagnostic method mechanics use
✅ Dashboard warning lights guide – what each light means and how urgent it is
✅ Live data cheat sheet – normal values for fuel trims, O2 sensors, voltage and temperature
✅ Symptom finder – start from what the car is doing and find the codes to look for

Who it’s for

DIYers who want to stop guessing, owners who want to understand a workshop quote before saying yes, and mechanics who want a fast reference on the bench. Works with any OBD-II scanner, including cheap Bluetooth adapters, on petrol and diesel cars (Europe from 2001/2004, USA from 1996).

The perfect companion to your AutoFixMaster library

Read the code with this handbook, then open your factory service manual and wiring diagram in the Member Area to find and test the exact component on your model.

Product details

📄 Digital PDF, 20 pages, A4 – read on PC, tablet or phone, or print it
⚡ Instant download after purchase
🌍 Language: English
📦 No physical item will be shipped

General information for generic OBD-II codes. Always follow your vehicle’s service manual and safety procedures.