The most likely reason for this problem is a clogged burner. Burners have multiple holes for feeding the gas. Unfortunately, their small size makes it rather easy for the burner to clog up – with either tiny food pieces or the oil tricking down on the burner.
In this case, it may be enough to simply brush the burner. Make sure the burner cap is not misplaced, since it may result in an uneven heating as well – or even prevent the burner from lighting up! It is better to simply clean the burner with the brush and avoid using cleaning detergents or other chemicals.

In case cleaning the burning does not help, there might be a clog deeper in the piping. Alternatively, the problem may lie in a broken gas valve that fails to supply an adequate amount of gas in the burner.

If you are unsure if your burners get gas or not, you may try to ignite the burners manually – with a match or a gas lighter. In case you fail to do so, you might indeed have a gas supply problem. In case you have a problem with a single burner the most likely cause is the malfunctioning knob assembly – it may be that the knob shaft does not turn, or maybe the valve itself is stuck and not turning properly. If none of your burners receives gas and the gas tank is not empty – the problem can be with the pressure regulator.

We would highly recommend avoiding repairing the pressure regulator on your own and invite a professional technician instead!

This is likely caused by a buildup of grease. In this case, it might be enough to simply clean the appliance and preheat it for around 10-15 minutes. Keep in mind that it is important to clean your grill regularly – no matter whether you are using a premium appliance or a cheaper brand!

If the igniter assembly breaks, you might not be able to light up the burners, even though you would hear the hissing of the gas. Again, this problem should be diagnosed more carefully before we can come to a conclusion what has to be done – sometimes it may be enough to replace the igniter itself, without replacing the knob or fixing the wires. While Viking grills are rather durable, sometimes the igniter assembly can become wet due to the weather conditions, which might result in a short and as a consequence – burning the electric components of your igniter.

Another reason for this issue could be that your grill’s battery is gone. It is important to point out that while batteries are commonly used in grills, not all Viking grills have them. If the problem is in the battery it may be enough to replace it, however it is also a good idea to check the rest of the assembly as well.