The S-code is used to identify what equipment level a unit had upon delivery. Such equipment could be standard on one market, but extra option on others.
Volvo don’t have information about S-codes for 1800 in their historical archive. We have to rely on spare part books and information from owners of 1800S, E and ES to decode the numbers. The list below is not at all complete and in some cases only assumptions based on photos in the 1800 register.
| S-code | Equipment | Model | Year | Market | Notes from the 1800 register |
| 1270 | P1800S | 1963 | -1 car -S-code on the same line as ch# on the ID-plate | ||
| 1320 | 1800S | 1966 | -1 car -S-code on the same line as ch# on the ID-plate | ||
| 5370 | Radiator in steel for the Nordic market | 1800S | 1968 | -2 cars -Scandinavia | |
| 5564 | Fan with slip clutch and a number of minor parts including water pump no 419679-6 | 1800S | -1 car -Switzerland | ||
| 5577 | Door mirrors | 1800S | 1969 | -10 cars -All 1800S 1969 | |
| 5589 | Cover for headrest Upholstery group 307 &317 Part no 693456-6 | 1800S | 1969 | -4 cars -1800S 1969 California white (42) and Black (19) -Upholstery 307-500 -USA and France (import from US) | |
| 5590 | Cover for headrest Upholstery group 308, 318 Part no 692659-6 | 1800S | 1969 | -6 cars -All red (46), all black upholstery (308-501) -Europe, USA and Panama | |
| 5591 | Cover for headrest Upholstery group 310, 320 Part no 692660-4 | 1800S | 1969 | -20 cars -All 1800S 1969 –All dark green (94) or blue (99) with brown upholstery (310-557) -Europe and USA | |
| 5912 | ? | 1800E | Japan | -1 car -1800E 1971 -Japan | |
| 5950 | Multi blade fan | 1800E | 1970-72 | USA | -12 cars -All 1800E 1970 -All California white (42) with red upholstery (327-625) -All with US spec. side indicators |
| 5951 | Air conditioner ? | 1800E | 1970-72 | USA & Canada | -91 cars -35 1800E 1970 -55 1800E 1971 -Some with US spec. side indicators |
| 5952 | ? | 1800E | 1970 | USA | -12 cars -All 1800E 1970 –All dark green (94) or blue (99) with brown upholstery -All with US spec. side indicators |
| 5955 | ? | 1800ES | 1972-73 | Australia | -13 cars -6 1800ES 1973 -7 1800ES 1972 -All in Australia |
| 5956 | ? | 1800E | 1971 | USA | -10 cars -All 1800E 1971 -All California white (42) with red upholstery (339-764) -All with US spec. side indicator |
| 5957 | US-specification | 1800E | 1971 | USA | -58 cars -All 1800E 1971 -All dark green (94) or gold metallic (105) -All except 3 1800E with US spec. side indicators |
| 5968 | Headlamp insert yellow halogen light with casing and bulb Part no 1212892-2 | France | No cars in the register with that code. Strange with the same number below (from the spare part book) | ||
| 5968 | Safety belt Part no 673051-9 | 1800E ch 30001-37549 | USA & Canada | ||
| 6008 | ? | 1800E 1800ES | 1972 | USA | -2 car -1 1800E 1972 -1 1800ES 1972 -US spec. side indicators |
| 6009 | ? | 1800E 1800ES | 1972 | -26 cars -20 1800ES 1972 -5 1800E 1972 | |
| 6010 | 1800ES 1800E | 1972 | -12 cars -10 1800ES 1972 -2 1800 E 1972 -Duel door mirrors on 1800E | ||
| 6026 | Safety belt Part no 1221033-2 | 1800ES | 1972-73 | -3 cars -2 1800ES 1973 -1 1800ES 1972 -All i Australia | |
| 6040 | Exhaust pipe Part no 673224-2 | 1800ES ch#3070- | 1973 | USA &Canada | |
| 6042 | Radio with roof mounted antenna? | 1800ES | 1973 | -5 cars -All 1800ES 1973 -All in Australia -All with roof mounted radio antenna | |
| 6044 | 1800ES | -3 cars -2 1800ES 1973 -1 1800ES 1972 -All in Australia | |||
| 6073 | ? | 1800ES? | 1973? | ||
| 6077 | US-specification | 1800E& ES | 1972 | USA | -73 cars -17 1800E 1972 -56 1800ES 1972 -All with US spec. side indicators |
| 6078 | US-specification | 1800ES | 1973 | USA | -161 cars -All 1800ES 1973 -All except a few with US spec. sideindicators |
| 6080 | Sun visor Part no L 1210418-8 Part no R 1210419-6 | 1800ES | 1972-73 | ||
| 6092 | 1800ES | 1973 | -1 car -Germany -Colour 115, Upholstery 458-886 | ||
| 6106 | ? | 1800ES | 1973 | -1 1800ES 1973 in Great Britain | |
| 6107 | ? | 1800ES | 1973 | -14 cars -1800ES 1973 -Great Britain, Australia and USA | |
| 6108 | 1800ES | ? | -30 cars -1800ES 1973 &1972 -3 in Sweden -22 in USA -1 in UK -1 in NL -1 in Denmark -1 in Japan | ||
| 6115 | 1800ES | 1973 | -1 car -Germany -Colour 115, Upholstery 458-886 |