Towards the end of September 1939, Krupp designed the "first real self-propelled artillery piece", the Sonderkraftfahrzeug 165/1 (Special Purpose Vehicle 165/1, abbreviated Sd.Kfz. 165/1).
After a series of tests, the Sd.Kfz. 165/1 was accepted by the Wehrmacht in early January 1940.
In 1941, Krupp built prototype vehicles armed with the 105 mm leichte Feldhaubitze 18/1 L/28 (light field howitzer 18/1 L/28, abbreviated leFH 18/1 L/28) cannon based on a modified Panzer IV chassis.
The prototypes were fitted with a smaller six-cylinder Maybach HL66P engine, which had a power capacity of 188 hp (140 kW).
Although 200 vehicles were ordered, Krupp completed only 10 prototypes in the final four months of 1942.[2These saw service on the Eastern Front.