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Service bulletins for the 2018 Hyundai Sonata

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

240 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Only bulletins with component: Automatic transmission are shown. Show all

Bulletins, newest first
21-AT-014H2021-09-17. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE; POWER TRAIN. Certain vehicles (listed below) equipped with 7-speed Double Clutch Transmissions (DCT) may exhibit abnormal vibration at low speeds. This bulletin outlines the procedures for diagnosing clutch judder, updating the Transmission Control Unit (TCU) with revised logic, and/or replacing the Double Clutch.
19-AT-018H2019-09-30. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. If you are servicing an applicable vehicle with a ?Check Engine? light on and one or more of the DTC listed below, follow the repair procedure and replace the related input/output speed sensor and oil pressure harness.
19-AT-015H2019-09-30. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; POWER TRAIN:AUTOMATIC TRANSMISSION; ENGINE. If you are servicing an applicable vehicle with a ?Check Engine? light on and one or more of the DTC listed below, follow the repair procedure and replace the related solenoid and oil pressure harness
5NP-P5L7D-052018-05-21. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; EQUIPMENT. If you are servicing a vehicle with a harsh and/or delayed shift, use the GDS as shown in the Service Procedure to measure shift engagement time.
5NP-L2K7X-052018-05-21. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. If you are servicing a vehicle with a harsh and/or delayed shift, use the GDS as shown in the Service Procedure to measure shift engagement time.
5NP-R6Y5M-012018-01-16. Service bulletin. POWER TRAIN; ELECTRICAL SYSTEM:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM). This bulletin provides information related to the Engine Control Module (ECM) and Transmission Control Module (TCM) software updates for certain 2018MY SONATA, equipped with 2.0L turbo engine and 8 speed automatic transmission. These vehicles may experience Malfunction Indication Light illumination with any of the following DTC(s) below: ? P219C: Cylinder #1 Imbalance Error ? P219D: Cylinder #2 Imbalance Error ? P219E: Cylinder #3 Imbalance Error ? P219F: Cylinder #4 Imbalance Error ? P0731: Gear 1 Incorrect Ratio
5NP-Z6F3A-112017-11-14. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:TORQUE CONVERTER. Before installing an automatic transmission, check the depth of the torque converter in the case to confirm the torque converter is fully installed in the transmission. If this is not done, the oil pump may be damaged.
5NP-B9K3N-102017-10-12. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. Some Sonata Hybrid (LF HEV) vehicles may experience a small oil leak from the electric oil pump (EOP) seals. If so, follow the Service Procedure in this bulletin to inspect and repair the oil seals between the transmission and EOP. No drivability issues are associated with this condition.
5NP-B6Z4E-102017-10-12. Service bulletin. POWER TRAIN; POWER TRAIN:AUTOMATIC TRANSMISSION. The 2018 Sonata (LFA) 2.0T is equipped with an 8-speed transmission. Do not replace the transmission for any of the solenoid DTC listed below. Instead, follow the Service Procedure on Page 2 and replace the related part.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.