I. Core Parameters and Specifications

Original Part Number: 309-5795 (3095795, CA3095795)

Replacement Models: 309-5769, 167-3466, 106-0179, 20PS767-13

Official Name: Travel Valve Pressure Switch / Hydraulic Pressure Switch

Type: Mechanical Pressure Switch (Normally Open), non-continuous analog output; triggers switch action only at the set pressure point.

Core Applications:

Monitors hydraulic pilot pressure (Boom / Stick / Bucket pilot circuits)

Monitors main pump / travel system pressure to trigger pressure protection functions

Used for hydraulic safety interlocks to prevent component damage caused by overpressure

Electrical Characteristics:

Operating Voltage: 12–32V DC (Compatible with 12V/24V systems)

Interface: 2-pin waterproof connector (Power + Ground)

Mechanical Parameters:

Housing Material: Alloy Brass

Operating Temperature: -40°C to 125°C

Protection Rating: IP67 (Waterproof and Dustproof)

Mounting Thread: M12×1.5 (Interchangeable with 309-5769)

Key Pressure Values (Core):

Closing Pressure (ON): 2646 ± 196 kPa (≈ 26.5 bar)

Reset Pressure (OFF): 2156 ± 196 kPa (≈ 21.6 bar)

(Pressure parameters are identical to 309-5769; this is an upgraded version of the same specification)

Accuracy: ±7% (Typical tolerance for pressure switches)

II. Compatible Engines and Equipment

Compatible Engines

C6.4 (Standard on 320D Series)

C13 (345D / 349D Series)

3046, 3054, 3056, 3066, 3126, 3126B, C-9, 3176C ...and others

Compatible Equipment (Mainstream Excavators)

311C / 312C / 313B / 314C / 315C / 318C / 319C Series

312D / 313D / 315D / 318D / 319D / 320D / 320D2 / 323D Series

324D / 326D / 329D / 330B / 330C / 336D / 345C / 345D / 349D Series

Newer models such as the 349D2, 349D2 L, etc.

III. Fault Symptoms and Diagnosis

Typical Fault Symptoms

Abnormal hydraulic operation (boom/stick/travel lacking power, sluggish movement)

Pilot/travel pressure alarms; ECM reports hydraulic pressure switch fault

Safety interlock failure; equipment enters torque-limiting mode or is unable to operate normally

Internal switch contacts are burnt/pitted or stuck, resulting in no signal output or a permanently closed circuit

Quick Diagnostic Steps

Continuity Test: Should be Normally Open (OPEN) when unpressurized; should Close (CLOSED) when pressurized to **≥ 26.5 bar**; should Open (OPEN) when pressure is relieved to **≤ 21.6 bar**.

Wiring Inspection: Measure voltage at the connector plug and check for proper grounding; troubleshoot for short circuits or open circuits.

Pressure Verification: Use a pressure gauge to verify that the switch accurately switches states at the 26.5 bar and 21.6 bar thresholds.

Substitution Test: Replace the component with a 309-5769 or 167-3466 unit to verify if the fault is resolved.