KSB solenoids are manufactured by Bosch, and are part of a cold start device (CSD) that increases the pressure in the fuel pump in some diesel engines. The increased pressure injects more fuel, allowing the vehicle to start on colder days.
A solenoid is a multi-use device consisting of wire that is coiled around a hollow core. When electrified, the iron center becomes magnetized and is pulled downwards into contact with electrical points that engage mechanical processes.
When the engine is below a certain temperature, a KSB solenoid engages. When the solenoid is activated it overrides the fuel pump in order to get more diesel into the starter system.
A KSB solenoid has two stages for different temperature conditions. Stage one engages when the vehicle is being started at temperatures between 44.6 and 68 degrees Fahrenheit, while stage two engages at temperatures below 44.6 degrees Fahrenheit. The solenoid disengages at temperatures above 68 degrees Fahrenheit, returning control of the fuel pump to the pressure regulator.
