2021 GMC Yukon XL fuel/propulsion system problems

“INCIDENT 1: Internal Engine Failure & Excessive Oil Consumption Component / System Failed: Engine Internal Components (Piston Rings, Valve Guide Seals, Spark Plugs) Failure Description: Excessive oil consumption (1.5 to 2.0 quarts burned every 2,000 miles) leading to heavy oil-fouling on spark plugs #5 and #7. Required complete cylinder head, oil pan, and piston teardown to replace all pistons, rings, connecting rod bearings, lifters, guides, valve guide seals, and spark plugs. Safety Risk: Severe internal engine oil consumption and plug fouling create an immediate risk of engine misfires, unexpected loss of power, or catastrophic engine failure while driving at highway speeds. Dealer / Repair Shop Confirmation: Confirmed by Dealership Service Department via oil consumption tests, spark plug inspection with oil dye, compression tests, cylinder leak-down tests, and physical teardown. Warning Symptoms: Low oil warning lamp illuminated; continuous need to top off oil between routine maintenance services. Inspection Availability: Vehicle and replaced components are available for inspection upon request.”

“INCIDENT 2: Total Electrical / Power System Shutdown Component / System Failed: Electrical / Power Control System (Auto-Stop/Start System) Failure Description: Total loss of electrical power causing the main dashboard and display screen to go completely dark, stalling the vehicle during an autostop event at a traffic light and preventing the engine from restarting. Safety Risk: Sudden total electrical shutdown leaves the vehicle completely dead, unresponsive, and immobilized in active traffic lanes/intersections, creating a high risk of rear-end or multi-vehicle collisions. Dealer / Repair Shop Confirmation: Customer complaint and active fault codes confirmed by dealership service department following standard maintenance schedule. Warning Symptoms: Display screen went blank; failure occurred instantly during autostop/traffic light stop without prior warning. Inspection Availability: Vehicle and affected systems are available for inspection upon request. INCIDENT 3: Fuel Pump Driver Module (FPDM) Failure Component / System Failed: Fuel Pump Driver Module (FPDM - Part #13554821) / Engine Control Module (ECM) Communication Failure Description: Total loss of…”

“INCIDENT 3: Fuel Pump Driver Module (FPDM) Failure Component / System Failed: Fuel Pump Driver Module (FPDM - Part #13554821) / Engine Control Module (ECM) Communication Failure Description: Total loss of communication between the ECM and FPDM, causing the engine to abruptly die while idling at a traffic light. Subsequent attempt to restart using push-to-start produced a severe mechanical screeching noise. Safety Risk: Unexpected stall in active traffic left the vehicle stranded and unable to restart safely, exposing occupants to collision hazards. Dealer / Repair Shop Confirmation: Confirmed by Service Technician. Diagnostic Code P129F ("ECM lost communication with fuel pump driver module") logged; verified power and ground failures at the module. Replaced FPDM (Part #13554821). Warning Symptoms: None prior to failure. Sudden engine shutdown followed by screeching sound on attempted restart. Inspection Availability: Vehicle and replaced module are available for inspection upon request.”

“INCIDENT 4: Fuel Injector Internal Short (Cylinder #6) Component / System Failed: Fuel Injection System / Cylinder #6 Fuel Injector & Wiring Harness Failure Description: Cylinder 6 fuel injector failed due to an internal electrical short circuit, causing immediate engine misfires and severe power reduction. Repair required replacing the Bank 2 fuel rail, four fuel injectors, and the injector wiring harness. Safety Risk: Immediate engine shuddering and abrupt drop in drive power while operating in active traffic creates a serious loss-of-acceleration hazard and heightened risk of a rear-end collision. Dealer / Repair Shop Confirmation: Official diagnosis confirmed by Service Center Technician via electronic diagnostics verifying the internal electrical short circuit. Warning Symptoms: Check Engine Light illuminated simultaneously with engine shaking and sudden power loss; no prior symptoms existed before the failure. Inspection Availability: Confirmed via technician diagnostics; Check Engine light illuminated along with four other warning lights- car had to be towed to dealership to be fixed”

“**Mileage at repair:** 76,165 miles **Component:** Fuel Pump Power Control Module While driving my 2021 GMC Yukon XL on [XXX] on a treacherous stretch decending [XXX] the engine unexpectedly stopped running, resulting in a complete loss of propulsion. This occurred on a section of interstate where there was no safe shoulder or suitable location to pull off the roadway. The unexpected failure created an extremely dangerous situation, exposing me and other motorists to the risk of a serious collision. The vehicle was subsequently towed, diagnosed and repaired by Darrell Waltrip Buick GMC in [XXX]. The dealership documented diagnostic trouble code P129F, "Fuel Pump Driver Control Module Fuel Pump Speed Signal Incorrect." The technician verified that the control module had proper electrical power, that there was no pin damage or connector fitment issue, and that the module required replacement. The dealership's written diagnosis specifically acknowledges that a failing fuel pump driver module can cause the engine to shut down. The original factory-installed module was replaced with GM part number 13554821, and the vehicle was subsequently tested and confirmed to…”

“part number 13554821 fuel pump control module has failed 2 times. April 2023 on Interstate 95 near Savannah GA in very busy traffic. Vehicle buckled and seized, just barely made it to the shoulder of the road. Same part failed again 9/18/26 while turning onto Sunrise Hwy in NY another very dangerous situation as we were stranded in the middle of a very busy intersection”