Hyundai Elantra 2019–2021 — technical service bulletin
Bulletin 22-EM-008H · NHTSA communication 10213724 · issued May 5, 2022
Technical service bulletin
communication type
Engine and Engine Cooling
component
2019–2021
model years
8
vehicle entries
Official summary
Hyundai is conducting a service campaign 974 to enhance the knock sensor logic with the Cylinder Noise Diagnostic System (CNDS) software update. CNDS is to detect abnormal cylinder wall scuffing or noise of the engine block before potentially severe engine damage occurs. If abnormal noise is detected, the Malfunction Indicator Lamp (MIL) will blink continuously. In addition, DTC P1327 will be recorded in the ECM.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.