Failure mode - Mercedes-Benz 3.0L V6 Diesel (Sprinter 2007-2022)

Turbo boost control: VNT actuator, leaks, limp episodes

Reliability tier: aggregated - verify before ordering, see /disclosure/

Symptoms

reduced power / limp mode with underboost DTCs
whistle or whoosh from leaking charge piping
boost DTCs that clear and return, worst under load on grades

Compare with the other causes of the same sign on this engine: loss of power, limp mode or derate (4 causes) · ticking, knocking, rattle or whine

Root cause

The OM642 runs a variable-nozzle turbo; boost control faults split between the actuator electronics, vane coking, and - the Sprinter-specific staple - the turbo inlet/charge piping leaks (a Sprinter parts retailer calls the inlet gasket the #1 OM642 fix it sees). NHTSA has a 12-complaint turbo/limp cluster (2007-heavy, 2012-2013).

Diagnosis

smoke-test the charge piping including the turbo inlet gasket before condemning the turbo
read boost setpoint vs actual PIDs under load
check VNT actuator linkage for coking/free movement; actuator electronics where DTCs point

Fixes

charge-pipe/inlet gasket renewal, actuator repair or turbo replacement per diagnosis ()

OM642 Turbocharger - Reman (642-090-12-00-83, current)

Prevalence

common