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Service bulletins for the 2020 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.

888 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.
N2023083202020-11-30. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY; EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.. Customer Satisfaction Program - Certain 2020 model year Cadillac CT4, CT5, and Chevrolet Corvette vehicles, equipped with the Cadillac User Experience with embedded navigation or the Infotainment 3 premium system w/navigation (RPO IOT), may have a condition where the radio display is non-functional except for the backup camera. The embedded Multi-Media Controller (eMMC) firmware contains a defect that could cause a continuous rebooting condition. Rebooting will continue even after shutdown, resulting in a battery drain for the affected vehicle, and possibly a dead battery and a no-start condition. Dealers will replace the radio receiver.
20NA2132020-11-30. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE AND ENGINE COOLING. This service bulletin provides information on Improved Oil Filter Gasket Design for Spin-On Oil Filters PF63, PF64 and PF48.
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.
PIC6391D2020-11-16. Service bulletin. SERVICE BRAKES, HYDRAULIC; ELECTRICAL SYSTEM. This PI communicates a parts restriction is in effect on 2020 Cadillac CT4, CT5 and Chevrolet Corvette Electronic Brake Boost Control Module and Valve Kit, Brake Pressure Modulator.
PIP5675G2020-11-16. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates to the dealer that a customer may comment that the MIL light is illuminated. The technician may find P1098 and/or P26BB set current or history. That this may be caused by a software anomaly, and that GM is currently looking into the issue. It provides testing and related direction based on the results.
PIP57602020-11-16. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the possibility of a flutter noise that can be transmitted through the engine mounts when the vehicle is operating in AFM mode.
PIC6390B2020-11-16. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a parts restriction is in place for the Central Gateway Module on 2020 Cadillac CT4, CT5, and Chevrolet Corvette.
PIP5675F2020-11-16. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates to the dealer that a customer may comment that the MIL light is illuminated. The technician may find P1098 and/or P26BB set current or history. That this may be caused by a software anomaly, and that GM is currently looking into the issue. It provides testing and related direction based on the results.
PIC6407D2020-11-16. Service bulletin. EQUIPMENT. This PI communicates a parts restriction is in effect on 2020 Cadillac CT4, CT5 and Chevrolet Corvette Amplifier.
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).
20NA1912020-10-26. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. This technical bulletin provides repair information to correct a customer concern of Auto Start/Stop Disabled with Malfunction Indicator Lamp (MIL) Illuminated and DTC U0599 set.
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.
N2023051802020-10-26. Service bulletin. FORWARD COLLISION AVOIDANCE: SENSING SYSTEM: CAMERA. Service Update Bulletin - Certain 2020 model year Cadillac CT4 and CT5 vehicles may have a condition where the front windshield camera module may reset and lose communication with other modules. DTCs P25A2, U0265, U0566 and U1962 are set. The malfunction indicator light (MIL) may illuminate. Reprogram the front view camera.
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
PIC6391C2020-10-19. Service bulletin. SERVICE BRAKES, HYDRAULIC; ELECTRICAL SYSTEM. This PI communicates a parts restriction is in effect on 2020 Cadillac CT4, CT5 and Chevrolet Corvette Electronic Brake Boost Control Module and Valve Kit, Brake Pressure Modulator.
PIC6407C2020-10-19. Service bulletin. EQUIPMENT:ELECTRICAL. This PI communicates a parts restriction is in effect on 2020 Cadillac CT4, CT5 and Chevrolet Corvette Amplifier.
PIC6387B2020-10-19. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a parts restriction is in place for the Short Range Radar Module on 2020 Cadillac CT4, and CT5.
PIC6394B2020-10-19. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a parts restriction is in place for the Image Processing Module on 2020 Cadillac CT4, and CT5.
PIC6404A2020-10-19. Service bulletin. ELECTRICAL SYSTEM; STEERING. This Preliminary information communicates An issue may occur causing a Service Driver Assist, Steering Assist Reduced Messages, or MIL illuminated with P25A2, U0265, and U0566, replacing the Front View Camera for frequently occurring cases and a software/hardware solution will be forthcoming for infrequently occurring cases.

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