How to troubleshoot a Vauxhall Vivaro engine that won't start?

I have a Vauxhall Vivaro that won't start. The engine doesn't even turn over. It was starting fine until a few days ago. What could be causing this issue and how can I fix it?

First, check the battery to make sure it has enough charge. If necessary, charge or replace the battery. If the battery is not the issue, check the fuse box for any blown fuses that could be preventing the engine from starting. If all fuses are intact, it could be an issue with the starter motor or ignition system.

Another possibility is a clogged fuel filter that is preventing fuel from reaching the engine. In this case, the fuel filter will need to be replaced. It is also worth checking the spark plugs and wires, as faulty ones could also be preventing the engine from starting.

If none of these solutions seem to be the problem, it could be an issue with the ECU or the fuel pump. It is recommended to take the vehicle to a certified mechanic for further diagnosis and repair.