Q.Sweet Pea Bush
My sweet pea bush has been in the ground over a year now, surviving one hot summer here in Phoenix. It looked beautiful this spring: green leaves and purple blooms all over. After the weather turned warm in May, it has started turning yellow and drying up. I’m hoping I can save it. I pruned back some of the dead areas, but would like any advice. Does it have a disease or pest problem?

Make sure you are growing your shrub in the correct location.
Sun in winter and shade in summer.
This article will help you.
https://www.gardeningknowhow.com/ornamental/shrubs/sweet-pea-shrubs/growing-sweet-pea-shrubs.htm