Komatsu PC400LC-7 and PC490LC-10/11: circuits and editions

PC400LC-7: breaker flow and opening-and-closing tools use different modes

The North American PC400LC-7 brochure describes four monitor modes: Active, Economy, Lifting and Breaker. In Active or Economy, the attachment circuit can receive two-pump flow in both directions. Breaker mode instead supplies one-pump flow in one direction, returning from the attachment to the tank.

A breaker demonstration therefore does not establish that an opening-and-closing tool has the correct circuit arrangement.

Its boom also has Smooth and Power settings. Smooth permits upward float while gathering blasted rock; Power increases the pushing action for harder digging. The Power Max button is a separate, temporary digging-force function.

Identify which setting the seller demonstrates before comparing the response with another excavator.

This edition offers a variable-gauge track frame as optional equipment. Its specification table separates fixed-gauge and variable-gauge weights, even with the same boom, arm, bucket and shoe width. A machine's model decal cannot tell you which weight or transport-width column applies.

Inspect the track frame itself.

PC490LC-10: particle-filter regeneration and attachment memories

The January 2017 European sheet identifies the SAA6D125E-6-A engine and EU Stage IIIB emissions specification. Its particulate filter uses an oxidation catalyst and active or passive regeneration. Cooled exhaust-gas recirculation is also described.

These are the equipment details to match when a seller discusses aftertreatment work; a later PC490LC-11's AdBlue system is a different specification.

Ten named attachment memories are provided on this version. Optional attachment lines and the standard quick-coupler power circuit serve different purposes, so the presence of a coupler does not establish that a hydraulic tool's working lines are installed. The sheet describes both pedal and sliding-joystick control arrangements for those additional functions.

Its headline engine output uses ISO14396, while the technical page separately gives ISO9249 net output. Keep the rating standard with the figure. A comparison that puts the headline against a neighbour's net rating would describe the measurement choice as though it were a machine improvement.

PC490LC-11: match the market and emissions edition

Komatsu's July 2024 European brochure specifies Stage V equipment. Its aftertreatment combines the particulate filter with selective catalytic reduction and an AdBlue tank. The earlier Stage IIIB sheet cannot supply the complete refill schedule for this arrangement.

Record the engine identification and emissions plate alongside the machine serial number when seeking parts or maintenance information.

Integrated Attachment Control provides fifteen tool presets for flow and pressure in this edition. The monitor also allows an adjustable idle-shutdown period, rather than merely displaying an idle caution. Those controls give a buyer specific functions to inspect, beyond a photograph showing that the display illuminates.

Bucket selection remains conditional on the front. The brochure separates mono-boom and short-boom schedules, then divides each by arm length and material density. Its maximum bucket headline consequently is not permission to fit that capacity to every arm.

Establish the installed boom and arm before using the bucket schedule or the corresponding reach and lift chart.