Question: "Can I send a P46(car) for Vans?" - the short answer is "No"!
As it's name suggest, the P46(car) facility ONLY allows the notification or cars to HMRC (be that provided, withdrawn, replacement etc). This process was put in place to allow 'in year' notification to HMRC of car changes as these tend to be elements that can make a significant change to a person's tax code. Equally, by nature of the way the calculation is carried out, the details can be different for every car.
Vans carry a more stable calculation (it is the same for all vans with the exception of shared/exclusive use), which means changes 'in year' are normally less significant. This means that vans can only be reported as part of the P11D process at the end of the year.
If an employee wants to affect their tax code during the year, their only option is to make a personal representation to HMRC, either via their personal tax account online, or by phoning into HMRC.