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Service bulletins for the 2021 Cadillac CT4

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.

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

By type

By component

By trouble code

By topic

Bulletins, newest first
060089026Q2020-12-07. Service bulletin. EQUIPMENT. This warranty administration bulletin provides information on Warranty Administration - Customer Concern Not Duplicated (CCND) Labor Operation Numbers.
050604022R2020-12-07. Service bulletin. FUEL SYSTEM, DIESEL. This bulletin provides information on the TOP TIER Detergent Gasoline Licensed Brands and the TOP TIER Diesel Fuel Licensed Brands that are recommended for use in all GM vehicles and the TOP TIER FUELS website URL.
20NA1962020-11-30. Service bulletin. ELECTRICAL SYSTEM. This service bulletin provides information and a service procedure for dealers/technicians on OnStar Over the Air Update for TTY / TDD Operation and Continuous Improvement Changes.
16NA2222020-11-30. Service bulletin. ENGINE. This bulletin provides information on Engine Concerns that could result from lack of scheduled maintenance, improper service or aftermarket calibrations.
110089005P2020-10-26. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This Warranty Administration bulletin provides information on Dealer Empowerment for Goodwill, Customer Enthusiasm and Policy (U.S. Only).
20NA1872020-10-26. Service bulletin. POWER TRAIN. This technical bulletin provides a repair procedure to correct a customer concern of Delayed and/or Harsh Engagement of Transmission Shift After Vehicle Sitting with Engine Off.
20NA1782020-10-26. Service bulletin. STEERING; ELECTRICAL SYSTEM. This technical bulletin provides repair information to correct a customer concern of Service Driver Assist and/or Take Steering Messages on Start-up, Advanced Driver Assist Systems (ADAS) Features Not Available.
20NA1572020-10-26. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. This bulletin provides information on the Transport Mode On Message Being Displayed in the Driver Information Center (DIC) and/or Battery Light is Flashing and the procedures to turn the Transport Mode message ON and OFF.
18NA3062020-10-26. Service bulletin. EQUIPMENT; STRUCTURE:BODY. This Warranty Administration bulletin provides information for dealers/Service advisors on when and how to submit a Pre-Repair Authorization (PRA) (US dealers only).
16NA0192020-10-26. Service bulletin. POWER TRAIN. This informational bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
PIP57552020-10-19. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the possibility of a engine oil leak that may occur at the cam carrier gasket T joint area due to improper amount of sealer be applied
20NA1592020-09-28. Service bulletin. TIRES. This Warranty Administration bulletin is for information on General Motors New Vehicle Tire Warranty Program (U.S. Dealers Only).
16NA3612020-09-28. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. This informational bulletin explains possible normal condition of a flare from 1st to 2nd, even if the trans had been repaired for the flare and its still noticed.

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