Komatsu Fault Code

Free · no signup

Event 311 / E311

Propulsion Cut / Retard Grid Alarm

System

Electric Propulsion

Symptom

Propulsion Cut / Retard Grid Alarm

Diagnosis & fix steps

LOGIC: Chopper Phase Module Collector-Emitter Desaturation Fault. ACTION: Check gate drive board power supply voltages. Inspect IGBT gate emitter resistance and verify high-voltage DC bus bar clamping torque on the failed phase.

Red Seal field insights

Inverter Dynamics: Prevents catastrophic explosion of high-power IGBT phase modules if gate control signals drop while high collector current is active.

Track this across your whole fleet

This code is free to read. AM Fleet Integrity lets your team log fault codes against assets, plus the full fault-code library, QR operator reporting, PM scheduling and predictive alerts. Start free — no credit card required.

Start your free trial

← All Komatsu fault codes