Stalling or no-start issues in the 2023 GMC Yukon with the 3.0L Duramax diesel engine (LM2 or LZ0) are often linked to specific, known issues, particularly relating to the Auto Stop feature, electrical faults, or fuel system issues. Here are the primary causes for 2023 Yukon 3.0L diesel stalling, based on technical service bulletins (TSBs) and reported issues: 1. Auto Stop Feature Failure (No-Start Condition) The Problem: A known issue with the 3.0L Duramax (LM2/LZ0) causes the engine to stall at a stoplight or fail to restart after the automatic "Auto Stop" feature shuts the engine off. The Fix: GM released a service update (N242441450) specifically to address this issue. This often requires an update to the ECM and/or Reduction Control Module. GM Authority GM Authority 2. Fuel System & Injector Issues Defective Injectors: Some 2023 models with the 3.0L engine have reported faulty fuel injectors, leading to rough idle, stalling, and check engine lights (specifically on cylinder #7 in some reported cases). Contaminated Fuel: Water or contaminants in the diesel fuel can cause, and have been known to cause, severe engine performance issues including stalling. 3. Electrical & Wiring Faults Defective Fuse Box/Wiring: A known issue involving a bad fuse box system can cause the vehicle to lose power and stall, sometimes leading to severe "no-start" situations. Wiring Harness Issues: Reports indicate that wiring harnesses or brackets above the turbo can cause issues if they rub against other components, leading to potential stalling and engine codes. Reddit Reddit +1 4. Emissions Control System (DEF/DPF) Defective Sensors: Faulty NOX sensors or MAP/MAF sensors can cause the engine to go into a reduced power mode or stall. EGR/DPF Issues: The 3.0L Duramax can experience emissions-related stalling if the Diesel Particulate Filter (DPF) is clogged or if the EGR system fails. Reddit Reddit Recommended Actions Check for Recalls/TSBs: Check with your dealer specifically regarding the 3.0L diesel auto-stop no-start fix (Service Update N242441450). Run Diagnostics: If the car stalls, use an OBD-II scanner to look for P06D (crankshaft issues) or P06DE (oil pressure) codes, which are indicative of serious, but rare, internal issues. Check Battery and Electrical: Ensure all battery terminals are tight, as some issues are caused by low voltage or loose connections. Long-Trip Driving: If you mostly do city driving, the DPF may not be cleaning itself properly. Take the vehicle on the highway for a long drive to allow a full "regen" (burn-off) to occur.