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Symptoms · Duramax LML (2011-2016)
Duramax LML (2011-2016): hard start, long crank or no-start
3 documented failures on this engine list this among their signs. They are ordered from the most widespread down. Each one shows the signs in its record's own words, how to tell it from the others, the usual fix and any recall or bulletin.
Not sure which engine you have, or want the recalls for your exact truck? Check your VIN: it names the engine and lists the campaigns for that model year. Whether a recall is still open on your VIN: nhtsa.gov/recalls.
verified
How widespread: Very common
How it shows up
- sudden loss of power / rough running, then a no-start as rail pressure collapses
Its other signs
- metal shavings in the fuel filter housing; the CP4's internal cam/c-roller wears through and sends debris down the high-pressure lines into the rails and injectors
- repair bills owners report at $7,000-$17,000 (NHTSA complaints 2016-2025): the documented outcome is a full tank-to-injector fuel system replacement, not just a pump
How to tell it apart
- cut open the fuel filter first: metal particles = CP4 cascade, stop cranking
- quantify rail pressure complaints (crank-no-start after a running event is the classic signature) before spending on injectors
- any pump replacement on a contaminated system must be paired with full-system decontamination - lines, rails, injectors, tank
Usual fix
full fuel-system decontamination (tank, lines, CP4 replacement, rails, injectors); the only reliable repair once metal is downstream
Recalls and bulletins
PIE0523 (A, B)PIP4949D / PIP4949EPIP5133 (A-D)PIP5151 (A-F)PIP4949B
Root cause, parts and sources →
aggregated
How widespread: Occasional
How it shows up
- hard starts only when cold; glow-plug circuit codes (often bank-specific)
Its other signs
- control-module faults after plug replacement without module check
How to tell it apart
- measure glow-plug resistance per plug; a failed module often kills a bank, not one plug
- check module fuses/harness before replacing plugs individually
Usual fix
replace failed glow plugs and/or the control module (couples with the CP4-era advice: minimize extended cranking on a weak-fuel system)
Root cause, parts and sources →
aggregated
How widespread: Occasional
How it shows up
- hard starting after sitting; one-cylinder miss under load
Its other signs
- injector balance/contribution codes, rough idle, fuel dilution of oil
How to tell it apart
- read injector balance rates per cylinder with a scan tool before ordering
- a return-flow/balance test separates electrical from mechanical injector faults
Usual fix
replace failed injectors (high-cost item; verify per-card revision windows inside 2011-2016)
Root cause, parts and sources →
Other symptoms on the Duramax LML (2011-2016)
Loss of power, limp mode or derateLosing coolantTicking, knocking, rattle or whineMisfire, rough idle, hesitation or surgingDEF, DPF and regeneration warnings
Everything on the Duramax LML (2011-2016)Its recalls and bulletins