Diagnostic Overview
Cummins fault code 2636 generally indicates turbocharger actuator performance or boost control mismatch. The ECM may command a turbo position but see air pressure, exhaust pressure, or actuator feedback that does not match. Causes include a sticking VGT mechanism, actuator failure, damaged actuator wiring, exhaust leaks before the turbo, charge-air leaks, faulty boost pressure sensor, or turbo mechanical binding. Recommended checks include actuator calibration, commanded versus actual position, charge-air leak testing, and inspection of the turbo linkage or vane movement.