1980 - 635 CSi get the DME
The most important change this year was that the 3.5 litre engine got the same DME as the 3.2 litre engine.
The 635 CSi also got a new rear spoiler and a new, more sophisticated, central locking system that could be controlled from the boot and from the passenger door.
Production numbers for 1980
| Model | Units | Total for model | Total all models |
| 628 CSi | 691 | 1018 | 6628 |
| 628 CSi A | 249 | ||
| 628 CSi RHD | 17 | ||
| 628 CSi A RHD | 61 | ||
| 633 CSi | 167 | 349 | |
| 633 CSi A | 182 | ||
| 633 CSi USA | 676 | 1328 | |
| 633 CSi A USA | 652 | ||
| 633 CSi A Japan | 366 | 366 | |
| 635 CSi | 2094 | 3567 | |
| 635 CSi A | 822 | ||
| 635 CSi RHD | 212 | ||
| 635 CSi A RHD | 439 |