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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.

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Only bulletins with component: Transmission and driveline are shown. Show all

Bulletins, newest first
24-AT-002H2024-04-16. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose and replace, if necessary, an automatic transmission with Incorrect Ratio DTC (transmission clutch slip in gear above limit) listed on Page 2.
23-AT-003H-12023-09-06. Service bulletin. POWER TRAIN. If you are servicing an 8-speed vehicle with a “Check Engine” light on and one or more of the DTC listed, follow the service procedure and replace the related solenoid and harness.
23-01-014H-52023-09-06. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Hyundai has launched an anti-theft software upgrade and window decal campaign (Campaign 993), combined with an anti-theft steering wheel lock campaign (Campaign P32), in response to an increase in thefts of certain 2011-2022MY Hyundai vehicles not equipped with engine immobilizers targeted through social media. For certain vehicles that cannot be updated with the software (Campaign 993), Hyundai is offering customers steering wheel locks at the dealer (Campaign P32). This Dealer Best Practices Guide provides information to assist dealership personnel with customer questions relating to the immobilizer software upgrade, window decals and steering wheel lock ant-theft solutions available from HMA through Hyundai dealers.
22-AT-007H2022-06-10. Service bulletin. POWER TRAIN; EQUIPMENT. 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.
22-AT-006H2022-06-10. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); POWER TRAIN. 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 harness.
22-AT-005H2022-05-10. Service bulletin. POWER TRAIN. 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 valve body harness.
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.
21-AT-001H2021-02-06. Service bulletin. POWER TRAIN. This bulletin provides the procedure to update the TCU for a rough idle in Drive with Neutral Control enabled. The rough idle may occur only at a stop in Drive with the A/C off and the ATF temperature between 158~210°F (70~99°C). This update also reduces vibration when the brake is released during Neutral Control operation and the accelerator pedal is depressed.
20-AT-005H-12020-11-06. Service bulletin. POWER TRAIN. 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 valve body harness.
20-AT-020H2020-10-08. Service bulletin. POWER TRAIN. This bulletin provides a procedure to transfer pressure data to the TCU using GDS Mobile. This procedure is necessary to reduce the transmission learning time and improve the shift quality.
20-AT-019H2020-06-06. Service bulletin. POWER TRAIN. If you are servicing any of the vehicles listed below with a harsh and/or delayed shift, use the GDS as shown in the Service Procedure to measure shift engagement time.
20-AT-017H2020-06-06. Service bulletin. POWER TRAIN. If you are servicing an applicable vehicle with the following symptoms and DTC, follow the Service Procedure on Page 4. • Check Engine light on • DTC P0880/P088000 - TCM Power signal error open/short • Transmission stuck in 4th gear fail-safe • Harsh shift into Reverse and Drive
20-AT-016H2020-05-07. Service bulletin. POWER TRAIN; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT ADAPTIVE/MOBILITY. The automatic transmission warranty repair policy authorizes in-dealership repairs of the following components for both OEM (new) and remanufactured automatic transmissions:
20-AT-014H2020-05-07. Service bulletin. POWER TRAIN; 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 solenoid and oil pressure harness.
20-AT-008H2020-03-07. Service bulletin. POWER TRAIN; EQUIPMENT; ELECTRICAL SYSTEM; 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 solenoid and oil pressure harness.
20-AT-001H2020-02-03. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose and repair a transaxle for the following Incorrect Ratio DTC (transaxle clutch slipping more than 200 rpm in gear).
19-AT-021H-12020-01-21. Service bulletin. POWER TRAIN; EQUIPMENT. If you are servicing a vehicle with a transmission slipping concern, follow the Service Procedure shown below and perform a stall test. This TSB provides a procedure to test each clutch in the transmission. If the vehicle fails the stall test, replace the transmission. ? PASS: Stall speed is between 1700~2900 rpm (See shop manual for stall speed). ? FAIL: Engine revs to redline limit (6,000~6,500 rpm). If so, replace the transmission.
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
19-AT-012H2019-07-29. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose and repair a transaxle for the following Incorrect Ratio DTC (transaxle clutch slipping more than 200 rpm in gear).
19-FL-003H2019-05-20. Service bulletin. POWER TRAIN; ELECTRICAL SYSTEM. This bulletin provides the procedure to write the Vehicle Identification Number (VIN) during the replacement of the Engine Control Module (ECM) or Powertrain Control Module (PCM). Once the VIN has been programmed to the ECM/PCM, it cannot be removed or overwritten.
5NP-T3A9N-122018-12-17. Service bulletin. POWER TRAIN. The vehicles listed below are equipped with an 8-speed front-wheel drive 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.
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-F6W6P-052018-05-21. Service bulletin. POWER TRAIN; POWER TRAIN:MANUAL TRANSMISSION:INTERNAL:GEARS; EQUIPMENT. The shift lever on some 6-speed vehicles may intermittently not shift out of Park. This bulletin provides the diagnostic procedures to correct this condition.

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