Sungai Besi to Nilai North The expressway begins at the Sungai Besi toll plaza. The
Kuala Lumpur–Seremban Expressway links Sungai Besi toll plaza to Jalan Istana and the
Besraya Expressway near the
Sungai Besi RMAF base. This section is a six-lane carriageway and serves the southwestern part of Klang Valley, passing by a few major towns. The expressway connects to Universiti Putra Malaysia via UPM Interchange, which also provides connection to other nearby suburban towns like Seri Kembangan via Besraya and Putrajaya via SKVE as well as Universiti Tenaga Nasional (UNITEN) nearby. Kajang interchange however is an interchange with Kajang SILK E18 on their Country Heights Interchange, before connecting it to Kajang town and the rest of E18 network. Bangi Interchange connects to Bandar Baru Bangi township and National University of Malaysia (UKM). The newly-built Southville City Interchange links to Federal Route 31 (Banting-Kajang Route), which provides access to Dengkil and Semenyih after passing the Southville City new developments. Putra Mahkota, the last interchange of the Selangor part of the route, connects to Bandar Seri Putra housing developments. The state border of Selangor-Negeri Sembilan follows after. This section only has laybys on Serdang and Nilai, with Nilai southbound also providing access to Nilai Memorial Park. However, what makes them different from other laybys is the food stall buildings are also present in these laybys, which makes their function similar to rest areas.
Nilai North to Seremban From this point the expressway enters Negeri Sembilan, running southwesterly towards Nilai. The interchange to
ELITE E6 lies in the northern part of Nilai, near the Selangor–Negeri Sembilan border, enabling motorists from the south to
Shah Alam and
Klang while bypassing Kuala Lumpur. This section has been widened to an eight-lane carriageway to accommodate heavy traffic. Nilai interchange gives access to Bandar Baru Nilai and Nilai 3 business centre. The expressway later continues to cross on Recron factory, quarries and estates and also the northernmost rest area of the route which is Seremban R&R. The latter only continues to Bandar Ainsdale Interchange, which links to Bandar Ainsdale new developments as well serving as the new northernmost interchange to Seremban. The Seremban Interchange provides direct access to Seremban city centre and also closes the gap between the expressway and Federal Route 1.
Seremban to Senawang This section links to Seremban City proper and Senawang. Between this section, there's Port Dickson interchange, which isn't connecting the expressway to Port Dickson town, but rather the Seremban-Port Dickson E29 expressway, which itself isn't directly connected to the expressway, but rather on the westward stretch of Federal Route 53 linked. The eight-lane dual-carriageway continues on this section. Senawang Interchange serves as southernmost interchange of Seremban area, which connects Senawang and Seremban Jaya residential areas. The route continues to run parallel to Federal Route 1.
Senawang to Ayer Keroh The expressway returns to a six-lane dual-carriageway with lanes are divided with a line of trees. This is the section where the route started back to distance from Federal Route 1 as the expressway routes into Malacca. Malacca-Negeri Sembilan border is situated a few kilometers before Simpang Ampat Interchange, and as the exit provides access to Simpang Ampat and Tampin nearby, it also being the last serving close connection to Federal Route 1 before both started to distance between them, with FT1 goes southeast, and E2 goes southwest into Malacca and run parallel, but distant from Lebuh AMJ FT19. Ayer Keroh is the only interchange that links close to the state's central areas, with a few kilometres north lies the only overhead restaurant of E2 which shares the same name.
Ayer Keroh to Pagoh The expressway becomes a four-lane dual-carriageway expressway. Along this section, the divider between lanes is decorated with flower trees instead. This is also the section where only the concrete pavement is done on this route, particularly between Ayer Keroh - Jasin part. The route started to go on its own route as FT19 became more distant and therefore ending after Malacca border, yet still so far with FT1 to close with. Past Sungai Kesang (Johor-Malacca border), the northernmost Johor exit is Tangkak, which aside from connecting to the textile border town, connects on FT23 which gives connection to major northwest towns of Johor, particularly close to Muar and further to Segamat. Both Bukit Gambir and Pagoh exits also provide connection to Muar. The northbound Pagoh R&R is also situated here.
Pagoh to Skudai The longest distance between two interchanges of the entire expressway lies in this section on Pagoh interchange to Yong Peng North interchange, a 42.98 km distance between both interchanges. As it also passes through Mount Maokil and surrounding hilly areas, a climbing lane is established on the section. The expressway finally connects to the Federal Route 1 directly via Yong Peng South exit, and going southbound both route runs back close in parallel until the terminus. Ayer Hitam interchange also connects to Federal Route 50, the central Johor main road which links the west coast and east coast part of the state from Batu Pahat to Mersing via Kluang as well as the ceramic town itself. The southernmost rest area for the whole expressway lies in Machap, just 2 kilometres from the Machap exit. The route then enters the Iskandar Johor corridor starting from Kulai interchange, which led towards Kulai town. The Senai North interchange links the expressway to the Second Link Expressway E3, which allow motorists a direct access to the Malaysia-Singapore Second Link Bridge to Tuas, Singapore, as well as connecting Senai airport areas before going southwest. The main route goes straight to Johor Bahru proper.
Skudai to Johor Bahru Closed toll fares begin and end on Skudai toll plaza, with Kempas toll plaza uses an open-toll collection system. The route continues to be linked parallel to Federal Route 1, with Skudai giving main access to Skudai town centre before going southeast to serve a few towns in Iskandar Puteri and Johor Bahru city areas. The route is also linked to Pasir Gudang Highway (FT17) on Pasir Gudang Interchange. On the last segment, the expressway finally terminates at its interchange with the
Johor Bahru Eastern Dispersal Link Expressway and is also the only part which links the route with Federal Route 3, the peninsular East Coast backbone. Both routes go down to the city centre and link to the Johor Causeway. ==Speed limits==