Fault Phenomenon: Komatsu HD605-7 mining truck engine power low, low boost pressure, high exhaust temperature.

Troubleshooting Process:
– Checked actuator: pneumatic or electric actuator push rod does not move.
– Checked valve plate: wastegate valve plate shaft corroded and seized.
– Checked air source: insufficient air pressure for pneumatic actuator.
– Checked linkage: linkage detached or deformed.

Root Cause: The turbocharger wastegate actuator push rod is stuck in the open position due to carbon buildup and high-temperature corrosion, causing exhaust gas to bypass the turbine directly.

Required Parts: Replace turbocharger actuator or repair wastegate mechanism.