2013 GMC Sierra 2500HD Problems: 9 Known Issues

On the 2011-2020 GMC Sierra 2500HD, the Bosch CP4.2 high-pressure fuel injection pump used on the 2011-2016 LML and 2017-2020 L5P Duramax diesel engines is prone to catastrophic failure that destroys the entire fuel injection system. Unlike its predecessor the CP3, the CP4.2 lacks a roller element and relies solely on fuel for lubrication. When metal fatigue occurs, the pump shatters and sends metal debris throughout the entire high-pressure fuel system — contaminating all six injectors, the fuel rails, return lines, and feed lines. Total repair cost runs $8,000-18,000. A class action lawsuit was filed against GM. The same pump also fails in Ford 6.7 Power Stroke and Ram 6.7 Cummins of the same era.

On the 2011-2016 GMC Sierra 2500HD 6.6L Duramax LML, the LML Duramax EGR (exhaust gas recirculation) cooler is prone to coolant leaks internally, allowing coolant to enter the intake manifold and combustion chambers. Coolant in the intake causes white smoke, rough running, and potential hydrolocking of cylinders. The EGR valve also sticks open or closed from carbon buildup, causing rough idle, black smoke, and check engine lights. The EGR cooler failure can occur as early as 60,000 miles on trucks used in stop-and-go driving. GM issued multiple TSBs addressing EGR cooler design improvements.

On the 2006-2016 GMC Sierra 2500HD, the Garrett variable-geometry turbocharger used on the LBZ, LMM and LML Duramax controls boost by pivoting vanes on a unison ring inside the turbine housing. Soot and carbon bake onto the ring over time and it begins to bind, so the actuator can no longer move the vanes to the commanded position. The ECM sees the mismatch and sets P003A (turbocharger position performance) and/or P2563 (turbocharger vane position sensor performance), usually together, and puts the truck in a reduced-power state. Trucks that idle a lot or run short trips soot the ring up fastest. Duramax forum and Diesel Place threads on these two codes run for hundreds of pages across 2006-2016 Sierra 2500HD trucks.

On the 2011-2015 GMC Sierra 2500HD, separate from the small-car ignition switch scandal, GM recalled full-size trucks including the Sierra 2500HD for an ignition lock actuator that binds inside the lock housing. The key becomes hard to turn, can stick in the START position, and can then snap back to ACCESSORY while the vehicle is being driven - shutting off the engine and with it the power steering and power brake assist, and disabling the air bags. NHTSA campaign 14V827000 covers the earlier population including 2012 Sierra 2500 trucks, and 15V640000 covers the later group including 2015 models.

On the 2003-2013 GMC Sierra 2500HD, gMT800 and early GMT900 Sierra 2500HD instrument clusters use tiny stepper motors to drive each needle, and those motors fail as a matter of course. The speedometer sticks, reads wildly wrong or flutters; the fuel, temperature, oil pressure and voltmeter needles drop dead or sit at false values. On a diesel HD truck the loss of the coolant temperature and oil pressure gauges is genuinely dangerous because the driver loses the early warning of an overheat. GM acknowledged the condition and ran Special Coverage Adjustment 07187C, extending coverage to 7 years/70,000 miles - that program has long since expired while the failures continue.

On the 2011-2025 GMC Sierra 2500HD, the Allison 1000 (gas) and Allison 2000 (diesel) 6-speed automatic transmissions used in Sierra 2500HD/3500HD are widely regarded as extremely durable, but the Transmission Control Module (TCM) and solenoid pack do develop faults. Common issues include harsh 1-2 shifts, transmission sticking in one gear, slip codes, and the truck going into limp mode (3rd gear only). The Allison's proprietary Transynd fluid is critical — using non-approved fluid is the leading cause of premature solenoid wear. TCM software updates from GM address most calibration-related shift complaints.

On the 2011-2016 GMC Sierra 2500HD 6.6L Duramax V8 (RPO LML), the 2011-2016 6.6L Duramax RPO LML added selective catalytic reduction, and the aftertreatment hardware is the engine's most frequent expense. The DEF tank heater and level/quality sender assembly fails often, the DEF (reductant) injector crystallizes and clogs, and pre-2015 NOx sensors drift out of calibration and report false "DEF quality poor" faults. Because these are emissions-critical, the truck gives a countdown of remaining miles and then enforces a hard speed limit - typically 65 mph then 4 mph - regardless of whether the DEF fluid is actually bad. Owners on duramaxforum.com and silveradosierra.com report P20EE, P249D and P22FE as the recurring set. This is LML-specific; the LMM has no DEF system.

On the 2011-2023 GMC Sierra 2500HD, sierra 2500HD 4WD trucks use a front axle disconnect system with an electronic actuator and Integrated Wheel End (IWE) hubs. The actuator motor and position sensor commonly fail between 80,000-120,000 miles, causing the 4WD system to not engage, to partially engage (binding and vibration), or to throw a 4WD Service warning. Heavy-duty truck use — particularly towing and off-road — accelerates actuator wear. The IWE hubs (vacuum-operated on some variants, electric on others) also fail, causing a grinding or clicking noise from the front axle in 2WD mode when the hub disengages incompletely.

On the 2001-2014 GMC Sierra 2500HD, the electric-shift NV246/NV263 transfer case on Sierra 2500HD trucks is positioned by an encoder motor mounted to the case, with a sensor ring inside it reporting shaft position back to the Transfer Case Control Module. Moisture and road salt corrode the encoder motor and its sensor ring, and the dash selector switch itself develops open contacts. When the TCCM loses a valid position signal it illuminates "Service 4WD" and refuses to shift. The classic pattern owners describe is a truck that will still drop into 4LO but will not engage 4HI, because the module can drive the case to its travel extremes but cannot stop it at the intermediate position. C0327 is the code that identifies it.