121-1491 Caterpillar Valve GP-Solenoid assembly, with a core of a 24V DC rotary proportional solenoid valve, primarily controls the flow, pressure, or rotation of the excavator's hydraulic pump, and is a key electro-hydraulic component for heavy equipment.

I. Core Parameters

• Model: 121-1491 (also written as 1211491, replacement part CA1211491)

• Type: Rotary Solenoid Valve

• Voltage: 24V DC (standard on most mainstream models, some are compatible with 12V, please refer to the vehicle model)

• Interface: 2-pin plug, standard hydraulic mounting position

• Material: High-strength alloy steel + heat-resistant coil, pressure-resistant and durable

• Compatible Engines: 3046, 3054, 3066, 3126, C4.4, C7.1, 3116, 3126B, 3306, C9, C-9, C13, C9.3, C18, 3176C, etc.

II. Functions and Applications

• Function: Receives ECU signals Electrical signals, via electromagnetic drive, rotate the valve core to regulate hydraulic oil flow, precisely controlling the swashplate angle of the hydraulic pump (adjusting flow and pressure) or switching the rotary motor oil circuit to match the speed, compound actions, and power output of the equipment. • Applicable Models (mainly excavators, covering multiple series): ◦ Mainstream Medium-sized: 311B, 311C, 311D LRR, 311F LRR, 312B, 312B L, 312C, 315B, 315B L, 315D L, 317B L, 317B LN, 318B, etc. ◦ Classic Popular: 320B, 320C, 320D, 321B, 321C, 322B, 322C, 324D, 324E, 325B, 325C, 325D, etc. ◦ Medium to Large Sizes: 326D, 329D, 329E, 330B, 330C, 330D, 336D, 336E, 345B, 345C, 345D, 349D, 365B, 365C, 385B, 385C, 390D, etc.

III. Alternatives and Pricing

Alternative Models: CTP H1211491, CA1211491, 457-9878 (Compatible in some scenarios)