CAT ET4 Diagnostic Interface (478-0235) | Caterpillar Heavy Equipment

What is the CAT ET4 — and what is it used for?

The CAT ET4 (NP 478-0235) is Caterpillar's official diagnostic interface for heavy machinery. With it, technicians can directly access the Electronic Control Modules (ECMs) of Caterpillar equipment from a computer, performing complete diagnostics, calibration, parameter adjustment, and software updates — without needing to disassemble components.

It replaces previous models 317-7485, 538-5051, and 171-4401 (CATII and CDL). With the included CAT ET v2023A software, it covers all Caterpillar equipment manufactured up to 2023, with support for ATA (J1708), J1939, and proprietary CAT networks.

ECM Tech Center sells and provides technical support for the CAT ET4. Please contact us before purchasing to confirm compatibility with your equipment model.

What you can do with the CAT ET4

Function	Description
Complete diagnostics	Access to all ECMs — engine, transmission, hydraulic, electrical
Fault code reading	Identifies and classifies DTCs by priority
Component calibration	Throttle calibration, timing, and hydraulic flow matching
ECM reprogramming	Updating and reprogramming control modules
Operational data analysis	Real-time monitoring: temperature, pressure, rotation, voltages
Diagnostic tests	Actuation of individual components for operation verification
Detailed reports	Generation of comprehensive reports for technical documentation

Equipment Compatibility

Covers the entire Caterpillar line up to 2023:

Construction and mining: track-type tractors, excavators, motor graders, wheel and track loaders, off-highway trucks, backhoe loaders, compactors, pavers, cold planers, forestry equipment, material handlers, pipelayers, compact loaders (skid steer and track), wheel excavators.

Underground equipment: hard rock loaders, longwall equipment, utility vehicles.

Power systems: electric power generation, marine power systems, oil and gas.

Protocols: ATA (J1708), J1939, and proprietary Caterpillar networks.

Technical Specifications

Field	Detail
Model	CAT ET4 — NP 478-0235
Replaces	317-7485, 538-5051, 171-4401
Software	CAT ET v2023A
Weight	1.5 kg
Dimensions	3 × 8 × 18 cm
Connection	USB
Operating system	Windows 7, 8 or 10 Pro (32/64 bit)
Condition	New