Your forklift is essentially confused about whether it should be moving or standing still. It "thinks" a command is being given even when you aren't touching the controls because the sensors are sending values slightly outside of the narrow pre-set neutral range .

Measure voltage across the battery terminals with no load (should be >24V). Then, activate the lift function while measuring. If voltage drops below 20V during lift attempt, before proceeding further.

"Alright, let's clear the code."

Marcus looked at Gretel. He remembered the week they’d overloaded her with 1,600 kg instead of 1,200. The time the night temp hit -30°C and they’d run her through frozen slush for three shifts without a clean. The grinding noise from the drive wheel he’d logged but not reported because “paperwork takes too long.”

The Jungheinrich drive controller contains power transistors (IGBTs) that switch voltage to the motor. If one IGBT fails to fire correctly, the motor runs on two phases instead of three. This drastically reduces speed and produces a huge negative deviation.