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Service bulletins for the 2020 Audi A8

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.

1291 on file from NHTSA, as of 2026-10-19.

About U1421 on the 2020 Audi A8: what the code means, and the bulletins and recalls about the same components.

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Only bulletins with trouble code: U1421 are shown. Show all

Bulletins, newest first
TSB_2056076_222025-04-04. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information when there is an SOS Malfunction with ConBox Low, "Emergency call function: fault", (DTC U142100, U153E00).
A9124522056076_212024-10-28. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information when there is an SOS Malfunction with ConBox Low, "Emergency call function: fault", (DTC U142100, U153E00).
A9123492056076_22023-12-06. Service bulletin. UNKNOWN OR OTHER; COMMUNICATION:MANUFACTURER TELEMATICS. This bulletin provides information when there is no diagnostics communication to the telematics control module in vehicles with ConBox low; DTC U142100.
A9123192056076_12023-09-01. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information for when there is no communication to the telematics control module, DTC U142100.
A9123082056076182023-07-10. Service bulletin. COMMUNICATION:MANUFACTURER TELEMATICS. Ths bulletin provides information for when no diagnostics communication to the telematics control module; DTC U142100 may be stored.
A9123702062973_42023-03-06. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. This bulletin provides information for when an SOS malfunction is displayed in the instrument cluster; DTCs U142100, U164200, and/or U122C00.
A9122442062973_32022-12-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin states that an SOS malfunction accompanied by DTCs U142100, U164200, and/or U122C100 my be stored erroneously and the ETCs should be cleared.
A9122332062973_22022-10-05. Service bulletin. EQUIPMENT:ELECTRICAL. This bulletin states that an SOS malfunction accompanied by DTCs U142100, U164200, and/or U122C100 my be stored erroneously and the ETCs should be cleared.
A9022732052299_52022-07-01. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin contains repair instructions for proper transport mode deactivation (DTC U142100, DTC P169A00, and U13EB00 ).
A9022462052299_42022-03-04. Service bulletin. EQUIPMENT. This bulletin contains repair instructions for proper transport mode deactivation (DTC U142100, DTC P169A00, and U13EB00 ).
A9121912062973_12021-05-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for when DTC U142100, U164200, and/or U122C00 are stored in the Gateway module with an SOS malfunction message in the instrument cluster.

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