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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.

Warranty extensions
N242480631-032025-06-18. UNKNOWN OR OTHER. Special Coverage. Certain vehicles listed above, may have a condition where the transmission control valve has worn, resulting in a gradual loss of pressure within the valve. The effects can cause harsh shifting, setting a service engine soon message, reduced engine performance or P0747 diagnostic trouble code. This special coverage covers vehicles that return after TCM Update Product Safety N242480630 and have P0747 condition described above for a period of 15 years or 150,000 miles (240,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after March 6, 2025, are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to March 6, 2025, must be submitted to the Service Contract provider. Vehicle owners or lessees who paid for repairs referenced in this Special Coverage (“Customers”) are eligible for reimbursement of their reasonable and customary expenses in accordance with the procedures specified below. The conditional right to reimbursement is provided by GM solely in the interest of customer satisfaction and is personal to Customers. Customers may not assign and GM does not consent to any assignment of any Customer’s right to submit reimbursement claims, or to receive reimbursement, or any other rights granted by this Special Coverage to any third party, including but not limited to service contract providers, and this Special Coverage is not intended to and does not confer any third party beneficiary, subrogation or contribution rights, or any other rights to reimbursement, against GM, whether in law, equity or otherwise, on any third parties. Dealers are to install a new control valve body. The repairs will be made at no charge to the customer.
N2424411202024-06-05. ENGINE. Special Coverage. Certain vehicles, equipped with a 2.0 gasoline engine (RPO LSY), may have a condition that could cause the evaporative emissions purge pump to fail. If this condition were to occur, the Malfunction Indicator Lamp (Check Engine Light) will illuminate, and a diagnostic trouble code will set. This special coverage covers the condition described above for a period of 15 years or 150,000 miles (240,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after June 5, 2024, are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to June 5, 2024, must be submitted to the Service Contract provider. Vehicle owners or lessees who paid for repairs referenced in this Special Coverage (“Customers”) are eligible for reimbursement of their reasonable and customary expenses in accordance with the procedures specified below. The conditional right to reimbursement is provided by GM solely in the interest of customer satisfaction and is personal to Customers. Customers may not assign and GM does not consent to any assignment of any Customer’s right to submit reimbursement claims, or to receive reimbursement, or any other rights granted by this Special Coverage to any third party, including but not limited to service contract providers, and this Special Coverage is not intended to and does not confer any third party beneficiary, subrogation or contribution rights, or any other rights to reimbursement, against GM, whether in law, equity or otherwise, on any third parties. Dealers are to replace the evaporative emissions purge pump as necessary. The repairs will be made at no charge to the customer.
22-NA-2442024-05-30. ELECTRICAL SYSTEM; EXTERIOR LIGHTING; STRUCTURE:BODY; UNKNOWN OR OTHER; SERVICE BRAKES. This service bulletin provides information about GM Accessories - Dealer-Installed, Repaired or Replaced During Warranty Coverage Period.

A warranty extension may pay for a repair after the basic warranty has ended. Read the document for which vehicles and which repair it covers.

By type

By component

By trouble code

By topic

Bulletins, newest first
PIT5698F2026-09-30. Service bulletin. UNKNOWN OR OTHER. This PI provides Diagnostics tips on how the LIN bus works and how to diagnosis it.
PIP5700H2026-09-29. Service bulletin. UNKNOWN OR OTHER. This PI communicates the proper part numbers for transmission connectors and internal harness to prevent confusion when ordering
PIC6555A2026-09-16. Service bulletin. UNKNOWN OR OTHER. This PI advises of a procedure for a Service Door Latch System message with No Related DTCs
PIP4902W2026-09-10. Service bulletin. UNKNOWN OR OTHER. This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIC6551C2026-08-27. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
PIT6446A2026-07-30. Service bulletin. UNKNOWN OR OTHER. This PI Communicates information to ensure Memory Recall is enabled to ensure memory mirrors return to set position after curbview assist is used.
PIT5099J2026-07-29. Service bulletin. UNKNOWN OR OTHER. PI to help diagnose A/C concern
PIT5966F2026-07-07. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.
PIP61152026-05-28. Service bulletin. UNKNOWN OR OTHER. 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.
PIT6215C2026-05-28. Service bulletin. UNKNOWN OR OTHER. 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.
PIC6423A2026-05-19. Service bulletin. UNKNOWN OR OTHER. Pi created to provide GM dealers with information on gathering information for projection issue
PIC6551B2026-05-19. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
PIT65112026-05-02. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates an issue with a replace or low FOB battery message
PIT65072026-04-29. Service bulletin. UNKNOWN OR OTHER. This PI communicates information on a SPS programming issue causing Serial Data Authentication Configuration to fail.
PIT3271Q2026-04-07. Service bulletin. UNKNOWN OR OTHER. This preliminary information communicates information about how to determine if a wheel and tires size change is available.
PIP61042026-03-17. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.
PIP4902V2026-03-17. Service bulletin. UNKNOWN OR OTHER. This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIT6425D2026-03-11. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC'ss
PIP5865L2026-02-18. Service bulletin. UNKNOWN OR OTHER. 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.
PIP5841H2026-02-09. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates the potential for condensation to freeze up inside the Crankcase Pressure Sensor causing dtc P04FB to set.
PIP5921B2026-02-01. Service bulletin. UNKNOWN OR OTHER. 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
PIP5865K2026-02-01. Service bulletin. UNKNOWN OR OTHER. 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.
PIT5985K2026-02-01. Service bulletin. UNKNOWN OR OTHER. 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.
PIP60982026-01-19. Service bulletin. UNKNOWN OR OTHER. This PI advised dealer technicians of possible causes of diesel fuel contamination in gasoline powered vehicles and advises of warranty direction.
PIT6425C2026-01-19. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC's

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