Cadillac CT4 Service Bulletins (2021)

810 manufacturer communications on file.

• August 20, 2026•Document ID: 11036392

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIC6551C

  Date Added:

  August 27, 2026

  Manufacturer:

  CHEVROLET

  Summary

  This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11036392-0001.pdf↗
• July 24, 2026•Document ID: 11035351

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6446A

  Date Added:

  July 30, 2026

  Manufacturer:

  CHEVROLET

  Summary

  This PI Communicates information to ensure Memory Recall is enabled to ensure memory mirrors return to set position after curbview assist is used.

  Associated Products (50)

  2026 Cadillac CT42026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Lyriq2026 Chevrolet Tahoe2026 GMC Hummer EV Pickup2026 GMC Hummer EV SUV2026 GMC Yukon2026 GMC Yukon XL2025 Cadillac CT42025 Cadillac Escalade2025 Cadillac Escalade ESV2025 Cadillac Escalade IQ2025 Cadillac Lyriq2025 Chevrolet Tahoe2025 GMC Hummer EV Pickup2025 GMC Hummer EV SUV2025 GMC Yukon2025 GMC Yukon XL+ 30 more
  Associated Documents

  • DownloadMC-11035351-0001.pdf↗
• July 21, 2026•Document ID: 11035340

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT5099J

  Date Added:

  July 29, 2026

  Manufacturer:

  CHEVROLET

  Summary

  PI to help diagnose A/C concern

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11035340-0001.pdf↗
• June 23, 2026•Document ID: 11034769

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT5966F

  Date Added:

  July 7, 2026

  Manufacturer:

  CHEVROLET

  Summary

  This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11034769-0001.pdf↗
• May 21, 2026•Document ID: 11032955

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP6115

  Date Added:

  May 28, 2026

  Manufacturer:

  GMC

  Summary

  The document advise technicians after an engine repair involving removal of the camshaft actuators, the vehicle may set p1101 P0172 and or stalls when taken off idle. The technician is instructed to verify the intake and exhaust camshaft actuators are installed onto the correct camshafts.

  Associated Products (14)

  2026 Cadillac CT42026 Chevrolet Colorado2026 GMC Canyon2025 Cadillac CT42025 Chevrolet Colorado2025 GMC Canyon2024 Cadillac CT42024 Chevrolet Colorado2024 GMC Canyon2023 Cadillac CT42023 Chevrolet Colorado2023 GMC Canyon2022 Cadillac CT42021 Cadillac CT4
  Associated Documents

  • DownloadMC-11032955-0001.pdf↗
• May 21, 2026•Document ID: 11032952

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6215C

  Date Added:

  May 28, 2026

  Manufacturer:

  CHEVROLET

  Summary

  This Preliminary information communicates to dealership technicians that if they encounter a customer vehicle with this concern, to perform the steps listed and should be able to reprogram the module and correct this.

  Associated Products (53)

  2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Chevrolet Colorado2026 Chevrolet Equinox2026 Chevrolet Tahoe2026 GMC Canyon2026 GMC Hummer EV Pickup2026 GMC Hummer EV SUV2026 GMC Terrain2026 GMC Yukon2026 GMC Yukon XL2025 Cadillac CT42025 Cadillac CT5+ 33 more
  Associated Documents

  • DownloadMC-11032952-0001.pdf↗
• May 11, 2026•Document ID: 11032764

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIC6423A

  Date Added:

  May 19, 2026

  Manufacturer:

  CADILLAC

  Summary

  Pi created to provide GM dealers with information on gathering information for projection issue

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11032764-0001.pdf↗
• May 11, 2026•Document ID: 11032763

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIC6551B

  Date Added:

  May 19, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11032763-0001.pdf↗
• April 25, 2026•Document ID: 11031948

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6511

  Date Added:

  May 2, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates an issue with a replace or low FOB battery message

  Associated Products (52)

  2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Lyriq2026 Cadillac Optiq2026 Chevrolet Tahoe2026 GMC Yukon2026 GMC Yukon XL2025 Cadillac CT42025 Cadillac CT52025 Cadillac Escalade2025 Cadillac Escalade ESV2025 Cadillac Lyriq2025 Cadillac Optiq2025 Chevrolet Tahoe2025 GMC Yukon2025 GMC Yukon XL2024 Cadillac CT42024 Cadillac CT5+ 32 more
  Associated Documents

  • DownloadMC-11031948-0001.pdf↗
• April 20, 2026•Document ID: 11031717

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6507

  Date Added:

  April 29, 2026

  Manufacturer:

  CADILLAC

  Summary

  This PI communicates information on a SPS programming issue causing Serial Data Authentication Configuration to fail.

  Associated Products (10)

  2021 Buick Envision2021 Cadillac CT42021 Cadillac CT52021 Cadillac Escalade2021 Cadillac Escalade ESV2021 Chevrolet Corvette2021 Chevrolet Suburban2021 Chevrolet Tahoe2021 GMC Yukon2021 GMC Yukon XL
  Associated Documents

  • DownloadMC-11031717-0001.pdf↗
• April 1, 2026•Document ID: 11030974

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT3271Q

  Date Added:

  April 7, 2026

  Manufacturer:

  CHEVROLET

  Summary

  This preliminary information communicates information about how to determine if a wheel and tires size change is available.

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11030974-0001.pdf↗
• March 9, 2026•Document ID: 11030092

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP6104

  Date Added:

  March 17, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11030092-0001.pdf↗
• March 9, 2026•Document ID: 11030091

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP4902V

  Date Added:

  March 17, 2026

  Manufacturer:

  BUICK

  Summary

  This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11030091-0001.pdf↗
• March 2, 2026•Document ID: 11029950

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6425D

  Date Added:

  March 11, 2026

  Manufacturer:

  BUICK

  Summary

  This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC'ss

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11029950-0001.pdf↗
• February 12, 2026•Document ID: 11028859

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP5865L

  Date Added:

  February 18, 2026

  Manufacturer:

  GMC

  Summary

  This Preliminary information communicates the possibility of DTC P30BF failing on low mile vehicles due to the possibility of the cylinder 1/2 sliding barrel binding on intake camshaft.

  Associated Products (14)

  2026 Cadillac CT42026 Chevrolet Colorado2026 GMC Canyon2025 Cadillac CT42025 Chevrolet Colorado2025 GMC Canyon2024 Cadillac CT42024 Chevrolet Colorado2024 GMC Canyon2023 Cadillac CT42023 Chevrolet Colorado2023 GMC Canyon2022 Cadillac CT42021 Cadillac CT4
  Associated Documents

  • DownloadMC-11028859-0001.pdf↗
• February 4, 2026•Document ID: 11028658

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP5841H

  Date Added:

  February 9, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates the potential for condensation to freeze up inside the Crankcase Pressure Sensor causing dtc P04FB to set.

  Associated Products (38)

  2025 Buick Envision2025 Cadillac CT42025 Cadillac CT52025 Cadillac XT42025 Cadillac XT52025 Cadillac XT62025 Chevrolet Blazer2024 Buick Envision2024 Cadillac CT42024 Cadillac CT52024 Cadillac XT42024 Cadillac XT52024 Cadillac XT62024 Chevrolet Blazer2023 Buick Envision2023 Cadillac CT42023 Cadillac CT52023 Cadillac XT42023 Cadillac XT52023 Cadillac XT6+ 18 more
  Associated Documents

  • DownloadMC-11028658-0001.pdf↗
• January 30, 2026•Document ID: 11027949

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP5921B

  Date Added:

  February 1, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates the possibility of DTC p0011 p0016 and potential for a rattle or ticking noise to occur from the Intake Cam Actuator, or cover plate screws backing out and making contact with Cam carrier

  Associated Products (3)

  2023 Cadillac CT42022 Cadillac CT42021 Cadillac CT4
  Associated Documents

  • DownloadMC-11027949-0001.pdf↗
• January 29, 2026•Document ID: 11027942

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIP5865K

  Date Added:

  February 1, 2026

  Manufacturer:

  GMC

  Summary

  This Preliminary information communicates the possibility of DTC P30BF failing on low mile vehicles due to the possibility of the cylinder 1/2 sliding barrel binding on intake camshaft.

  Associated Products (14)

  2026 Cadillac CT42026 Chevrolet Colorado2026 GMC Canyon2025 Cadillac CT42025 Chevrolet Colorado2025 GMC Canyon2024 Cadillac CT42024 Chevrolet Colorado2024 GMC Canyon2023 Cadillac CT42023 Chevrolet Colorado2023 GMC Canyon2022 Cadillac CT42021 Cadillac CT4
  Associated Documents

  • DownloadMC-11027942-0001.pdf↗
• January 27, 2026•Document ID: 11027932

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT5985K

  Date Added:

  February 1, 2026

  Manufacturer:

  CADILLAC

  Summary

  This PI provides diagnostics tips to dealership techs when trying to diagnose a CAN Bus communication issue after an event like a lightning strike, battery jump started backwards, failure over the air update, etc.

  Associated Products (85)

  2026 Buick Enclave2026 Buick Envision2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Chevrolet Colorado2026 Chevrolet Equinox2026 Chevrolet Tahoe2026 Chevrolet Traverse2026 GMC Acadia2026 GMC Canyon2026 GMC Hummer EV Pickup2026 GMC Hummer EV SUV2026 GMC Yukon2026 GMC Yukon XL2025 Buick Enclave2025 Buick Envision+ 65 more
  Associated Documents

  • DownloadMC-11027932-0001.pdf↗
• January 16, 2026•Document ID: 11027697

  Service Bulletin/Repair Instructions
  UNKNOWN OR OTHER

  Mfr Comm. #:

  PIT6425C

  Date Added:

  January 19, 2026

  Manufacturer:

  CADILLAC

  Summary

  This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC's

  Associated Products (210)

  2026 Buick Enclave2026 Buick Encore2026 Buick Encore GX2026 Buick Envision2026 Buick Envista2026 Cadillac Celestiq2026 Cadillac CT42026 Cadillac CT52026 Cadillac Escalade2026 Cadillac Escalade ESV2026 Cadillac Escalade IQ2026 Cadillac Escalade IQL2026 Cadillac Lyriq2026 Cadillac Optiq2026 Cadillac Vistiq2026 Cadillac XT42026 Cadillac XT52026 Cadillac XT62026 Chevrolet Blazer2026 Chevrolet Colorado+ 190 more
  Associated Documents

  • DownloadMC-11027697-0001.pdf↗