What does 221 mean in a code for a volvo 940?

In a Volvo 940, the code 221 typically refers to a fault in the vehicle's fuel system, specifically indicating a problem with the fuel injection system or a malfunction related to the fuel pressure. This code may suggest issues such as a faulty fuel pump, clogged fuel filter, or problems with the fuel injectors themselves. It's advisable to perform a thorough diagnostic check to identify the exact cause and ensure proper repairs are made.