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Service bulletins for the 2020 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.

124 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.
24-FL-002H2024-03-05. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); ENGINE AND ENGINE COOLING. This bulletin provides the procedure to update the Engine Control Module (ECM) and/or the Transmission Control Module (TCM) for 2020-2023MY Sonata (DN8/DN8a) vehicles to improve operation of the Idle Stop and Go (ISG) system. Under certain circumstances the vehicle may not restart after the ISG system has engaged and requires a manual restart due to the lack of intake manifold pressure recovery.
23-EM-009H2023-12-22. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. Certain 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles may exhibit coolant leakage, engine overheating, and white smoke from the exhaust due to an internal leak at the Exhaust Heat Recovery System (EHRS) portion of the center muffler assembly. Follow the procedure outlined in this bulletin to repair this condition after confirming EHRS is leaking internally.
23-01-093H2023-12-22. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. This bulletin provides the procedure to update the Hybrid Control Unit (HCU) and Dual Automatic Temperature Control (DATC) software to help improve coolant flow to the Exhaust Heat Recovery System (EHRS).
23-AT-006H-22023-11-30. Service bulletin. POWER TRAIN. This TSB provides information to diagnose the push button shifter operation.
23-AT-008H-12023-10-02. Service bulletin. POWER TRAIN. If you are servicing an 8-speed front-wheel-drive vehicle equipped with automatic transaxle with one or more of the DTC or symptoms listed below, refer to the Service Procedure to diagnose the condition. • DIAGNOSTIC TROUBLE CODES: ➢ P070500 - Transmission range sensor circuit malfunction ➢ P070512 - Transmission range sensor circuit malfunction ➢ P070514 - Transmission range sensor circuit malfunction ➢ P07051C - Transmission range sensor circuit malfunction ➢ P070600 - Transmission range sensor circuit range/performance ➢ P070661 - Transmission range sensor circuit range/performance ➢ P070696 - Transmission range sensor circuit range/performance • SYMPTOMS: ➢ Malfunction Indicator Light (MIL) illuminated ➢ 5th gear fail-safe ➢ Intermittently won’t shift into D or R ➢ Intermittently won’t shift out of Park ➢ Intermittent ly no engine cr ank/n o start in “P” or “N” with or without MIL or DTC.
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-HC-002H2023-09-06. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); POWER TRAIN. This bulletin provides information related to the Engine Control Module (ECM) software update and coolant replacement for 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles to improve the coolant filling mode by discharging air bubbles.
23-AT-006H-12023-09-05. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; POWER TRAIN. This TSB provides information to diagnose the push button shifter operation. If you are servicing a vehicle with any symptoms listed below or DTCs (listed on Page 2) , follow the Service Procedure on Page 3. SYMPTOMS: • “Shifter System Malfunction” displayed in the cluster • Won’t shift into or out of gear or won’t shift out of Park • Incorrect gear display in cluster and/or won’t start
23-AT-008H2023-08-02. Service bulletin. POWER TRAIN. If you are servicing an 8-speed front-wheel-drive vehicle equipped with automatic transaxle with one or more of the DTC or symptoms listed below, refer to the Service Procedure to diagnose the condition.
22-AT-010H2022-08-24. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING. If you are servicing an applicable vehicle with a “Check Engine” light on and one or more of the DTC listed below, follow the Service Procedure and replace the valve body internal harness and the input/output speed sensor.
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.
22-AT-001H2022-02-08. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose the push button shifter operation. If you are servicing a vehicle with any symptoms or DTC listed below, follow the Service Procedure, Page 2.
21-AT-009H2021-08-07. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose the push button shifter operation.
21-AT-007H2021-07-09. Service bulletin. POWER TRAIN. If you are servicing an 8-speed front-wheel-drive vehicle with the DTC or symptoms listed below, refer to the Service Procedure to diagnose the condition. • DIAGNOSTIC TROUBLE CODES: • P070500 - Transmission range sensor circuit malfunction • P070512 - Transmission range sensor circuit malfunction • P070514 - Transmission range sensor circuit malfunction • P07051C - Transmission range sensor circuit malfunction • P070600 - Transmission range sensor circuit range/performance • P070661 - Transmission range sensor circuit range/performance • P070696 - Transmission range sensor circuit range/performance • SYMPTOMS: • Malfunction Indicator Light (MIL) illuminated • 5th gear fail-safe • No gear indication in cluster • Intermittently won’t shift into D or R • Intermittently won’t shift out of Park • Intermittent ly no engine cr ank/no start in “P” or “N” with or without MIL or DTC.
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-FL-004H2020-06-06. Service bulletin. SERVICE BRAKES, HYDRAULIC; ENGINE AND ENGINE COOLING; POWER TRAIN. This bulletin describes the Idle Stop and Go (ISG) system operation, diagnostic and battery sensor recalibration procedure. Refer to applicable Shop Manual and Owner’s Manual for additional information.
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-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-DS-001H(1)2020-05-07. Service bulletin. POWER TRAIN; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT:MECHANICAL. Certain 2020MY Sonata (DN8) vehicles may exhibit a grease leak coming from the right side, inner CV axle boot area. This bulletin describes the procedure to replace the right side CV axle boot on the differential side (inner) on certain 2020MY Sonata (DN8) vehicles.
20-AT-006H2020-03-07. Service bulletin. POWER TRAIN; ENGINE. If you are servicing an 8-speed front-wheel-drive vehicle with the DTC or symptoms listed below, refer to the Service Procedure to diagnose the condition.
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).

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