#N202319660: Service Update - Valve Spring Failure - (Nov 20, 2020)

NOTE: THIS RECALL IS VIN SPECIFIC AND YOU WILL RECEIVE A LETTER IF IT APPLIES TO YOUR VEHICLE

Subject: N202319660 — Valve Spring Failure

Models: 2021 Cadillac Escalade (RPO L87)
2021 Chevrolet Camaro (RPO LT1/LT4)
2020 Chevrolet Corvette (RPO LT2)
2020–2021 Chevrolet Silverado 1500 (L87)
2021 Chevrolet Suburban (L87)
2021 Chevrolet Tahoe (L87)
2021–2021 GMC Sierra 1500 (RPO L87)
2021 GMC Yukon (L87)



Important: The following inspection procedure does not need to be performed on any dealer courtesy or demo vehicle with 500 miles (800 km) or more. Please use labor code 9105460to close the field action.
Inspection Procedure 1. Ensure vehicle has a ½ tank of fuel minimum.
 2. Set vehicle up in a secure area where it cannot be stolen, with adequate ventilation (use exhaust vent hose if indoors) andopen the hood or engine compartment lid. Keep vehicle away from any flammable surroundings or substances. Ensure the A/Cis off. Finally, position a box fan blowing at the vehicle’s radiator.
◦For Corvette Convertible, remove the folding top stowage compartment lid. Refer to Folding Top Stowage Compartment Lid Replacement in SI. Then, pause the convertible top halfway up, and position a box fan blowing down into the engine compartment. Be surethe area around the coolant reservoir is getting adequate airflow.
◦For Corvette Coupe, position a box fan blowing down into the engine compartment. Be sure the area around the coolant reservoiris getting adequate airflow.
◦For Manual Transmission equipped vehicles, be sure the vehicle has the parking brake engaged, the vehicles wheels are chocked,and the transmission is in neutral before performing the following steps.
 3. Apply the brake and start the vehicle, holding the Engine Start/Stop button for at least 15 seconds.
◦At this point, C8 Corvettes and T1 SUVs will display an “Automatic Shutdown Disabled” message on the DIC.
◦Other vehicles will not display this message on the DIC, but by holding the Engine Start/Stop button for 15 seconds, the featurewill still be activated on T1 Trucks and Camaros.
 4. Set up your laptop in the vehicle, plugging the charging cable into the vehicle’s 110v power plug (or use an extension cordif the vehicle is not so equipped), and the MDI 2 into the vehicle’s OBDII port.
 5. Open Techline Connect and navigate through GDS2.
◦Select K20 Engine Control Module > Control Functions > Engine Speed/Throttle > Engine Speed.
◦Drag the slider to the right until the engine’s idle speed is set to 2,000 RPM.
 6. Using your phone or a timer you can keep near you, set a timer for 4 hours and 30 minutes and allow the vehicle to run.
 7. Check on the vehicle at a minimum of 25-minute intervals to ensure it is still running, and run down the below checklist – the more often you can check on it, the better. The checklist includes:
◦Normal Engine Operating Temperature
◦No abnormal valve train noise
◦No check engine light (especially P0300 or P030X)
◦No abnormal burning smells (catalytic converter break-in smell is normal operation).
◦Look underneath the vehicle and ensure there are no leaks.
 8. If for some reason the vehicle does shut off during the test, restart it per the original instructions and continue the testfrom the time point where the vehicle shut off. It is not necessary to restart the entire test.
 9. If any of these conditions are detected, immediately stop the test, immediately call the GM Technical Assistance Center forfurther instructions. For U.S. Dealers contact 877-446-8227. For Canadian Dealers contact 800-263-7740 (English) or 800-263-7960(French). For International Dealers, if any of these conditions are detected, follow normal diagnostic and parts orderingprocedures.
10. If 4.5 hours passes and none of these conditions are detected, replace any removed components and take the vehicle for a 10mile test drive. Ensure the computer and MDI remain in the vehicle during this test drive so you can check DTCs if necessary.Utilize manual shifting mode for the entire duration of the test drive, attempting to keep RPM between 2000 and 3500 RPM.During the test drive, monitor for the below conditions. Ifany of these conditions are found during the test drive, immediately return to the dealership, keeping the engine RPM as lowas possible and avoiding heavy throttle.
◦Normal Engine Operating Temperature
◦No abnormal valve train noise
◦No check engine light (especially P0300 or P030X)
◦No abnormal burning smells (catalytic converter break-in smell is normal operation).
11. If both the high-idle test and the road test complete successfully without any of the above described issues, no further testingis required.
12. Perform an oil change. Refer to Engine Oil and Oil Filter Replacement in SI.