Get the app
Quick access from your home screen.
AV-SCANNER / Service function guides / Engine and oil
This guide explains how to use camshaft and crankshaft correlation data to judge timing chain wear on engines where the chain drives the camshaft. It is written for working mechanics and experienced DIYers who already understand engine timing fundamentals and have access to a scan tool with live data. You will learn how to prepare the vehicle, capture and interpret correlation readings, compare them against the manufacturer's specification, and decide whether the chain is stretched. The guide also covers vehicle-specific differences, common mistakes, troubleshooting failed tests, and aftercare so you can complete the job professionally and avoid comebacks.
Guidance is general and covers many makes. Exact procedures and values vary by model, so confirm them in the factory service information for your vehicle.
Download all 12 sections as a branded PDF to use in the workshop.
Get the app
Quick access from your home screen.