Trouble codes › By vehicle › Chevrolet Silverado 2500HD and 3500HD
Common check-engine codes on the Chevrolet Silverado 2500HD and 3500HD
2011-2025
Silverado HD and GMC Sierra HD pickups share their engines: the 6.6L Duramax diesel (LML 2011-2016, L5P from 2017) or a gas V8 (6.0L, then the 6.6L from 2020). The 2011-2016 LML's Bosch CP4.2 fuel pump is the best-known weak point; the L5P switched to a Denso pump. Most other diesel codes come from the emissions equipment (particulate filter, DEF and EGR).
Most common: P0087, P2463, P20EE, P0401, P0299, P0300.
Known problems on the Chevrolet Silverado 2500HD and 3500HD
P0087 Fuel Rail/System Pressure - Too Low
P0087 means fuel rail pressure is lower than the engine computer commanded, from a weak pump, clogged filter or failing high-pressure pump.
On the Chevrolet Silverado 2500HD and 3500HD: On the 2011-2016 LML Duramax, low rail pressure (often with P0088 or P0191) can be the start of a CP4.2 pump failure, which can send metal through the whole fuel system within minutes. Stop and have it checked; don't keep driving to see if it clears. Check the fuel filter and water separator first. The 2017+ L5P uses a different (Denso) pump.
P0087: causes, can I keep driving, and what to check first →
P2463 Diesel Particulate Filter Restriction - Soot Accumulation (Bank 1)
P2463 means the diesel particulate filter (DPF) is clogged with soot that normal regeneration hasn't cleared.
On the Chevrolet Silverado 2500HD and 3500HD: Soot loading in the particulate filter: short trips and idling stop it regenerating. Check the DPF pressure sensor and hoses, then try a long highway drive or a scan-tool regen.
P2463: causes, can I keep driving, and what to check first →
P20EE SCR NOx Catalyst Efficiency Below Threshold (Bank 1)
P20EE means the diesel SCR (DEF) system isn't cutting NOx enough, often from bad DEF, a NOx sensor or software needing an update.
On the Chevrolet Silverado 2500HD and 3500HD: DEF (SCR) efficiency: DEF quality, a failing NOx sensor, a clogged DEF injector or an exhaust leak. It leads to reduced speed if ignored.
P20EE: causes, can I keep driving, and what to check first →
P0401 Exhaust Gas Recirculation "A" Flow Insufficient Detected
P0401 means the EGR system isn't flowing enough exhaust back into the intake, usually from carbon-clogged passages or a stuck valve.
On the Chevrolet Silverado 2500HD and 3500HD: EGR flow: the LML's EGR valve and cooler are known to clog with soot or fail. Watch the coolant level for a leaking cooler.
P0401: causes, can I keep driving, and what to check first →
P0299 Turbocharger/Supercharger "A" Underboost Condition
P0299 means the turbo or supercharger isn't making the boost the engine asked for, most often from a boost leak.
On the Chevrolet Silverado 2500HD and 3500HD: Underboost: check for boost leaks at the intercooler pipes and boots first, then the turbo's vane control.
P0299: causes, can I keep driving, and what to check first →
P0300 Random/Multiple Cylinder Misfire Detected
P0300 means the engine is misfiring in more than one cylinder, often from worn plugs or coils, a vacuum leak or low fuel pressure.
On the Chevrolet Silverado 2500HD and 3500HD: Gas engines: plugs, coils and wires first; on high-mileage 6.6L gas engines, carbon on the intake valves and weak injectors have caused misfires too.
P0300: causes, can I keep driving, and what to check first →
Got a code on your Chevrolet Silverado 2500HD and 3500HD?
iRepair researches your exact year, engine and code (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.
Ask iRepair about your Chevrolet Silverado 2500HD and 3500HDNo scanner? Most auto parts stores read check-engine codes for free.
Common codes and known problems as widely reported for these model years; your vehicle may differ. Check nhtsa.gov/recalls and ask a dealer about service bulletins for your VIN, and confirm in your service information.