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

Glow plug module and cold-start roughness

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

Symptoms

glow plug warning lamp flashing (cylinder-level fault indication)
cold-start roughness/white haze that fades as the engine warms
hard starts specifically on cold mornings

Compare with the other causes of the same sign on this engine: hard start, long crank or no-start (2 causes) · white smoke from the exhaust · misfire, rough idle, hesitation or surging (4 causes)

Root cause

The OM642 glow plug module is a known Mercedes-diesel wear item (the module drives the plugs and reports cylinder-level faults; the flashing lamp is the classic tell). Community consensus tier - VOQ shows no distinct glow cluster (the pulled complaints fold cold-start into the fuel branch).

Diagnosis

read glow module DTCs per cylinder; the flashing lamp usually names the failing cylinder
measure plug resistance per cylinder before condemning the module
verify battery health first - weak cranking mimics glow faults

Fixes

glow plug(s) and/or module replacement per diagnosis ()

glow-plug - more than one option: OM642 Glow Plug Module (current, 642-900-13-02), OM642 Glow Plug Module (2010-2013, 642-900-14-02), OM642 Glow Plug (001-159-71-01, 2010-2013)

Prevalence

common