How do you change a timing chain on a Toyota Echo?

To change the timing chain on a Toyota Echo, first disconnect the battery and remove any components obstructing access to the timing cover, such as the engine mount, alternator, and belts. Then, remove the timing cover to expose the timing chain. Align the timing marks on the crankshaft and camshaft gears, remove the old chain and tensioner, and install the new chain, ensuring proper alignment. Finally, reassemble all components, replace the timing cover, and reconnect the battery.