If you are investigating a cold engine that cranks but will not start, save every stored and pending code before clearing anything. Save stored and pending codes; compare engine speed during cranking and the security-system status if available. Record the engine temperature and load alongside the reading; the same value can mean different things in different conditions.
A basic reader may not access every module. Check battery connections and recent service before assuming the fuel pump or ignition system has failed. Use the exact vehicle’s service information to interpret the result.
Quick educational note
For information, not a diagnosis or repair instruction. Vehicle-specific checks are still required. Consult the manufacturer's guidance and a qualified technician.
How to use this information
This article explains general principles and does not establish what is wrong with your vehicle. Read the content limitations.