This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have a Service Engine Soon Malfunction Indicator Lamp on at low mileage. Technician may find Diagnostic Trouble Codes P0420 and or P0430 stored. Technician should be advised that the catalytic converter efficiency Diagnostic Trouble Codes P0420 and P0430 are disabled for the first hour of engine run time to allow break-in of the catalytic converter. Technician will need to use a Tech2 to check the verify engine run time on the Engine Hour Meter in the Instrument Panel Cluster Data Display/Data 1 List in the scan tool match. If the engine run time is less tha
full bulletin at NHTSA ↗2015 GMC Sierra engine problems
moderate 49 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
49
Recalls
0
Avg fix
$3,100
1fire
What stands out
Owners have filed 49 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
No new NHTSA engine complaint has been filed on this vehicle in over 9 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
THIS INFORMATIONAL BULLETIN PROVIDES THE TECHNICIAN WITH WHAT MAY HAPPEN TO AN ENGINE DUE TO LACK OF MAINTENANCE.
full bulletin at NHTSA ↗THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLE THAT MAY HAVE BLACK SMOKE ON A COLD START. A DUAL-PULSE INJECTION STRATEGY IS UTILIZED DURING ENGINE COLD START TO REDUCE THE TIME REQUIRED TO BRING THE CATALYTIC CONVERTER UP TO OPERATING TEMPERATURE. THIS SPLIT INJECTION STRATEGY LASTS FOR ABOUT 60 SECONDS ON COLD START. THIS PROCESS MAY CAUSE THE CUSTOMER TO SEE INCREASED BLACK SMOKE DURING COLD START AND SHOULD BE CONSIDERED NORMAL.
full bulletin at NHTSA ↗THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT MAY HAVE A COLD ENGINE TICK NOISE FOR 50 SECONDS AT START UP. TECHNICIAN DETERMINES IF THE TICK NOISE IS POSSIBLY COMING FROM THE EXHAUST MANIFOLD, AS THIS NOISE COULD EASILY BE MISTAKEN FOR AN ENGINE TICK NOISE. IF YOUR SI DIAGNOSIS DOES NOT ISOLATE THE CAUSE OF THIS CONCERN, THIS CONCERN SHOULD BE CONSIDERED A VEHICLE DESIGN CHARACTERISTIC OF THE ECM CALIBRATION AND NO ADDITIONAL REPAIRS SHOULD BE PERFORMED.
full bulletin at NHTSA ↗This informational bulletin provides information on close coupled converters and there affect on newly installed engines or engines during there break in period.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2015 GMC Sierra exhibits recurring engine problems centered on AFM (Active Fuel Management) lifter collapse, which owners describe happening at 40,000 to 100,000+ miles. When a lifter fails, it bends push rods, damages the camshaft, and triggers cylinder misfire with a distinctive ticking or knocking sound, rough idle, and loss of power. Repairs run $2,852 to $18,000 depending on damage scope. Critically, multiple owners report lifter failure recurring after dealer repair at lower mileages, suggesting incomplete fixes. GM issued recall NHTSA 25V274000 for certain lifter failures but owners say it excludes 2015 model year despite the defect clearly affecting that year.
Radiator leaks are another pattern: owners report stress cracks forming from thermostat cycling or weld failures, allowing coolant loss starting as early as 25,000 miles. Replacement radiators from GM also leak, frustrating owners. GM recalled 2014 Sierra for the same issue but refuses to recall 2015, telling owners "not enough complaints."
AC condenser leaks are frequent, with refrigerant escaping at welds or seams; dealers cite this as known defective welding but no recall exists. One owner also reported engine fire while parked, resulting in loss of brakes and hand injury. Throttle response delay affects drivability; the manufacturer claims it is normal, which owners dispute. Stalling, complete engine seizure, and rod bearing failure represent the most severe failures.
Same GMC Sierra engine reports on nearby years: 2013 · 2014 · 2017 · 2018
Failure modes owners describe
AFM/Lifter Failure
Active Fuel Management (AFM) system lifters collapse or fail, bending push rods and damaging camshaft, leading to cylinder misfire, loss of power, knocking/ticking sounds, and engine damage.
When: 40,000 to 100,000+ miles; multiple owners report recurrence at lower mileages after repair
Symptoms owners cite: Ticking or knocking sound from engine; Rough idle and shaking; Loss of power while driving; Check engine light with cylinder misfire codes (P0307, etc.); Rough running engine; Flashing check engine light in some cases; Metal fragments in oil system
Codes mentioned: P0307, Misfire detected on various cylinders
Repairs/costs cited: Lifter replacement with push rod replacement, ranging $2,852 to $18,000+ for rebuild/replacement. Multiple owners report lifter failure recurring after repair. One owner paid $10,754 for AFM lifter and push rod replacement, then needed catastrophic engine replacement later.
Recalls/TSBs owners mention: GM issued recall NHTSA Campaign Number 25V274000 for certain lifter failures, but owners report recall does not cover 2015 model year despite known defect dating back further. No bulletins provided for early failures. Extended warranty programs mentioned by one owner.
Emission System Limp Mode
Engine enters limp mode and reduces vehicle speed progressively (75 mph → 55 mph → 4 mph) in response to emission system faults, creating highway safety hazard.
When: Occurred while driving on highway; problem repeated after dealership repair attempt
Symptoms owners cite: Engine light illuminates with 'Emission needs serviced' message; Progressive speed reduction while driving; Loss of acceleration and inability to merge in traffic; No acceleration capability to avoid hazards
Repairs/costs cited: One owner reports dealership 'fixed' the issue under powertrain warranty but problem recurred within 700 miles of driving. No repair details provided.
Recalls/TSBs owners mention: Owner took vehicle back to dealership under powertrain warranty; no successful resolution documented
Radiator Leak
Radiator develops leaks due to stress cracks from thermostat cycling or weld/connection failures, causing coolant loss and overheating.
When: 25,000 to 78,000 miles; appears to be design defect affecting multiple model years
Symptoms owners cite: Coolant smell detected; Low coolant reservoir; Visible fluid under vehicle; Engine temperature rises and cooling fan runs continuously
Repairs/costs cited: Radiator replacement cost $1,200–$1,400. Multiple owners report replacement radiators also fail. One owner replaced original radiator and new GM radiator (part 84207654) also began leaking.
Recalls/TSBs owners mention: GM issued recall for 2014 Sierra 1500 for same issue but not 2015, despite known defect. Service bulletins PI1513F and GM bulletins referenced for 2014–2015 models with special coverage for certain models. Dealers telling owners 'not enough complaints' for 2015 recall.
Air Conditioning Condenser Failure
AC condenser develops leaks at welds or seams, losing refrigerant and causing AC system failure.
When: 25,000 to high mileage
Symptoms owners cite: AC blows warm air; Refrigerant loss; AC system inoperative; Defrost may not operate
Repairs/costs cited: Condenser replacement cost $800–$1,300. One dealership mechanic confirmed receiving multiple complaints and stated it is a known problem with weld failure in coils. Repairs failed to hold charge in one case.
Recalls/TSBs owners mention: No recalls issued. Dealership mechanic stated they were surprised GM had not recalled despite it being a known problem.
Engine Seizure and Fire
Engine seized while driving; separate incident involved engine fire while parked that affected braking and resulted in severe damage.
When: Fire incident at 124,000 miles; seizure at 40 mph mid-traffic
Symptoms owners cite: Popping noises from engine compartment before seizure; Loss of motive power; Flames from hood; Smoke from engine compartment; Loss of brake function (fire incident)
Repairs/costs cited: Fire vehicle not repaired; seizure vehicle not inspected or repaired. Owner sustained minor hand injury from fire incident.
Recalls/TSBs owners mention: Manufacturer not notified of fire incident. No manufacturer response documented.
Rod Bearing Failure
Rod bearings fail, damaging lifters and creating violent vibration and loss of power.
When: 43,000 miles and 122,000 miles in reported cases
Symptoms owners cite: Violent vibration while driving; Warning lights illuminated; Loss of motive power; Black smoke from exhaust
Codes mentioned: Technical Service Bulletin 20-NA-038
Repairs/costs cited: Rod bearings and lifters require replacement. Estimated cost not provided in narratives. One vehicle not repaired; another repaired.
Recalls/TSBs owners mention: Manufacturer notified in one case; referred to dealer. TSB 20-NA-038 documented.
Cylinder Compression Loss
Cylinder loses compression due to lifter failure or internal engine damage, causing misfire and rough running.
When: Detected after coolant system issues or during routine diagnosis; occurred at various mileages
Symptoms owners cite: No compression in cylinder (typically #7); Rough idle and shaking; Check engine light with misfire code; Large smoke from tailpipe; Traction control light illuminated; Vehicle running rough as if in 'limp mode'
Repairs/costs cited: Requires engine work involving lifter repair. One owner's repair took from November 2021 to January 2022 due to parts shortage, costing thousands.
Recalls/TSBs owners mention: Dealership confirmed diagnosis and performed repair (extended timeline due to parts availability).
Radiator and Transmission Failure
Simultaneous failure of radiator and transmission; loud pop heard before loss of power.
When: At 65 mph and 170,000 miles
Symptoms owners cite: Loud popping noise in engine; Condensation on road; Loss of motive power at low speed; Vehicle went into limp mode
Repairs/costs cited: Radiator and transmission required replacement at one instance; engine required replacement at another instance on same vehicle. Vehicle ultimately repaired.
Recalls/TSBs owners mention: Manufacturer notified of failure.
Throttle Response Delay
Engine exhibits delayed response to throttle input at all speeds and during acceleration from stop, affecting drivability and safety.
When: Ongoing issue at all speeds
Symptoms owners cite: Delay in acceleration response from idle; Delay at all driving speeds
Repairs/costs cited: No repair documented. Dealer confirmed issue during test drive but manufacturer claimed normal operation.
Recalls/TSBs owners mention: Manufacturer stated the delay is normal operation; owner disputes this claim.
Engine Stall and Shutdown
Engine stalls while driving, sometimes repeatedly, with check engine light, requiring restart or complete engine replacement.
When: 97,000 miles (stall with restart); multiple instances of engine failure
Symptoms owners cite: Engine stalls while driving; Check engine warning light; Engine dies at stop signs and random times
Repairs/costs cited: One owner's vehicle stalled and restarted but was diagnosed as needing engine replacement (not repaired). Another owner's engine died multiple times over eight weeks with no resolution after three shop visits.
Recalls/TSBs owners mention: Manufacturer made aware; dealer suggested dealership service. No resolution documented.
Engine Head Failure
Engine heads develop faults causing coolant leaks and fluid loss.
When: Before 78,000 miles
Symptoms owners cite: Fluid leak under truck; Faulty engine heads
Repairs/costs cited: Engine heads required replacement and machining after parts arrival, causing extended repair time.
Recalls/TSBs owners mention: Dealership performed diagnosis and repair; owner contacted GMC complaint department with no documented help by June 2015.
Synthesized from 49 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
I bought this truck new in 4/2106 and there is a clicking sound when engine is running. Is this normal?
Had engine trouble with your 2015 GMC Sierra?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2015 GMC Sierra?
It's a documented issue but not catastrophic. 49 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 23 complaints that reported odometer mileage, most engine failures cluster between 47,000 and 97,000 miles, with the median around 75,000. A quarter of owners report trouble before 47,000; a quarter make it past 97,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2015/GMC/Sierra.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.