New Implement Software is Now Used on Certain Wheel Tractor-Scrappers Equipped With Cat® Grade Control {7620} Caterpillar

Wheel Tractor-Scraper

621H (S/N: DBK1-131)

623H (S/N: DBF1-UP)

627H (S/N: LCT1-UP; DBW1-348)

Reference: Special Instruction, REHS7209, "Installation, Calibration, and Measure up of the Cat^® Grade Control System for the H-Series Wheel Tractor-Scrappers".

Description Of Change: New implement software is now used on the machines that are listed above. The new software has following improvements for the H-Series Wheel Tractor-Scrappers:

• Improved the response of the system after completing a turn or a turn on a side slope for machines equipped with Cat^® Grade Control.

• Reduced the magnitude of the cut/fill difference and the time for the system to recover has been made faster for machines equipped with Cat^® Grade Control.

• Updated the rear disconnect communication diagnostics logic.

• Increased diagnostic debounce time for auto/manual and mode select switches.

• Updated diagnostic debounce times for Cushion Hitch, Implement Lockout and Bail switches.

Note: Limitations may exist with turn calculations of a single Global Navigation Satellite System (GNSS) system but the recover is faster with the new software.

Adaptable To: The new implement software is adaptable to the products within the listed serial numbers, and is effective with all products after the listed serial numbers.

The new implement software part number is listed in Table 1.

Note: A new chassis angle sensor calibration and 7 point measure-up will be required for the Cat Grade Control system after completing the software update. Refer to the above mentioned reference for calibration instructions and procedures.