In March of 2012 we had shifting problems with the Allison transmission at Compestela en route to PV. Next day a service truck arrived from Guadalajara and were unable to resolve the issue. They suggested that we drive to the shop in Guadalajara and they would follow in the service truck. Without going into details (Available on our BLOG) another issue (loss of air)developed at the toll booth to the 15D from Compestela. They were able to repair it and also then found and repaired the burnt wiring causing the shifting problem.
20km further south at Ahuacatlán we were able to make a returno and head north on the 15D. Northbound we didn't notice (or don't remember) seeing an exit from the 15D to Compestela.
Our question: IS there an exit to Compestela southbound from that point on the 15D? It might be worth taking the bypass then back to Compestela. Certainly it might be worth it north bound from PV to avoid the road from Compestela through Xalisco.