274-6721 Cat Low Pressure Sensor: Primarily utilized for monitoring engine oil pressure, low fuel pressure, and low intake/aftertreatment system pressure, it serves as a critical component for ECM control and low-pressure system protection. I. Core Parameters and Specifications

Part Number: 274-6721 (2746721, CA2746721)

Official Name: Pressure Sensor (Low-Pressure Type) / Oil Pressure Sensor / Fuel Pressure Sensor

Type: Strain Gauge / Capacitive Low-Pressure Sensor

Primary Applications:

Monitoring Engine Oil Pressure (Primary Use)

Monitoring Low-Pressure Fuel System Pressure (Low-Pressure Fuel Pump / Pre-Fuel Rail)

Monitoring Intake Air Pressure and Aftertreatment Low Pressure (Specific Engine Models)

Electrical: 3-Pin DT Waterproof Connector; 5V Power Supply; 0.5–4.5V Analog Voltage Output (Voltage increases with pressure)

Mechanical: Thread M12×1.5 / 7/16-20 UNF; Brass Alloy Housing; IP67 Protection Rating; Operating Temperature -40°C to 125°C

Measurement Range: 0–20 bar (0–2 MPa) [Low-Pressure Range]

Accuracy: ±0.5% FS

Replacement Models: U5MK1074, U5MK1088 (Compatible with Perkins / Cat)

II. Compatible Engines and Equipment (Mainstream Models)

Engines

C4.2, C4.4, C6.4, C6.6, C7, C9, C18, C32, C175-16

Perkins 1104C, 1106C, 1106D Series

Excavators (Wheeled / Tracked)

Tracked: 311D, 312D, 313D, 318D, 319D, 320D, 323D

Wheeled: M313C, M315C, M316C, M318C, M322C

Loaders / Scrapers / Trucks

Loaders: 924G, 928G, 928GZ, IT28G, 432E Articulated Trucks: 793F, 794AC, 795F

Others: TH350B, TH580B Telehandlers; CP-563E, AP-655C Compactors / Pavers

III. Fault Manifestations and Diagnosis

Typical Symptoms

Engine oil pressure alarm; low oil pressure protection activation; engine torque derating / shutdown

Low fuel pressure alarm; difficulty starting; unstable idle; insufficient power

ECM reports faults regarding pressure sensor circuits, ranges, or performance

Abnormal pressure display on the instrument panel (reading too high / too low / no display)

Common Fault Codes (CAT)

P0520/P0521/P0522/P0523: Engine oil pressure sensor circuit faults

P0191/P0192/P0193: Low fuel pressure sensor circuit faults

Quick Checks

Verify that the 5V reference voltage and ground connections are normal

Measure the output voltage at idle and under pressure (0 pressure ≈ 0.5V; full scale ≈ 4.5V; linear variation)

Check for loose connectors, corrosion, or water ingress; verify the sensor's mounting seal integrity and tightening torque