DIAGNOSIS When one side drives slower, it's almost always a calibration issue with the drive control levers, not a mechanical failure. The sensors that read the lever positions can get out of sync.
FIX You need to perform a drive calibration. Here's how. 1) Park on a flat, level surface. Turn the key on but do NOT start the mower. 2) Move both drive levers fully outward to neutral. 3) Now, without touching the levers, press and hold the "Blade Engage" button and the "Headlight" button simultaneously for about 5 seconds until the display changes. 4) The screen will guide you through moving the levers slowly forward to their stops, then back to neutral, then backward to their stops. Follow the prompts exactly. 5) When it's done, the display will return to normal. Take it for a slow test drive to see if the pull is corrected.
IF THAT DIDN'T WORK If calibration doesn't fix it, check the tire pressures. A significantly underinflated tire on one side will also cause a pull. Inflate all tires to the recommended PSI listed on the tire sidewall or in .
HEADS UP Perform this calibration on a level surface. If the mower is parked on a slope, the calibration can be thrown off because the system uses internal sensors to find true neutral.