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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
17-NA-0732023-03-03. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This warranty administration bulletin provides information regarding the field action courtesy transportation policy.
PI0754F2023-03-03. Service bulletin. VISIBILITY:GLASS, SIDE/REAR:CRITICAL FASTENERS; UNKNOWN OR OTHER; STRUCTURE. This PI provides information on Rear and Side Tempered Glass Spots (Quench Marks) and that they are a normal characteristic.
99-04-20-002N2023-03-03. Service bulletin. POWER TRAIN. This service bulletin provides information on Driveline Clunk Noise and what is acceptable and what is considered normal operation.
18-NA-2632023-02-28. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This warranty administration bulletin provides policy information for variable diagnostic time allowances on select labor operations (U.S. Only).
13-03-10-001J2023-02-28. Service bulletin. WHEELS. This service bulletin provides information on summer tire performance and tire cold weather cracking.
01-08-42-001O2023-02-28. Service bulletin. EXTERIOR LIGHTING. This service bulletin provides information for dealers/technicians on Exterior Lamp Condensation and Water Leaks and Replacement Guidelines.
21-NA-1062023-02-23. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. This service bulletin provides information for the technician that may experience a condition when after performing a DTC Clear/Reset on the TCM during diagnosis or after completion of a transmission repair or replacement, the DTCs did not clear or appear to reset on the next engine start.
18-NA-2792023-02-23. Service bulletin. EXTERIOR LIGHTING; LATCHES/LOCKS/LINKAGES; EQUIPMENT. This service bulletin provides information for dealers/technicians on the process to disable and enable passive unlocking.
17-NA-2392023-02-23. Service bulletin. SERVICE BRAKES, HYDRAULIC. This bulletin provides information on possible normal brake drag caused by the vehicle parked for an extended period of time.
22-NA-2002023-02-21. Service bulletin. EQUIPMENT; LATCHES/LOCKS/LINKAGES; ELECTRICAL SYSTEM. This service bulletin provides repair information to correct a customer concern of Child Safety Lock Update failure.
22-NA-1152023-02-21. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. This service bulletin provides information for U.S. dealers ONLY to refer to the Battery Maintenance Report to identify vehicles in dealer inventory that require attention.
PIT5832E2023-02-13. Service bulletin. COMMUNICATION. This Preliminary information communicates a diagnostic tip on how to resolve a issue if the serial data authentication configuration did not complete correctly.
PIP5841B2023-02-13. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:CRANKCASE (PCV). This Preliminary information communicates the potential for condensation to freeze up inside the Crankcase Pressure Sensor causing dtc P04FB to set.
PIT59712023-02-13. Service bulletin. EQUIPMENT:ELECTRICAL. This Preliminary information communicates to the technician that GM is aware of this concern with audio loss and the OnStar LED being red. GM is working on a solution to correct this customers concern.
PIT59692023-02-13. Service bulletin. ELECTRICAL SYSTEM; VISIBILITY. This Preliminary information communicates an issues with the side blind alert icon not working properly after a short range radar is replaced. Dealers are to perform a return to factory settings to correct the issue.
PIT5966A2023-02-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.
PIP5843B2023-02-13. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.
PIP5889A2023-02-13. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the possibility of dtc p0299 due to a stuck open Charge Air Bypass Valve
PIT5762F2023-02-13. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. This Preliminary information communicates an issues with false codes setting in vehicles due to timing issues between the modules.
07-03-16-004E2023-02-08. Service bulletin. EQUIPMENT; WHEELS; TIRES:PRESSURE MONITORING AND REGULATING SYSTEMS. This service bulletin provides information for tire pressure monitoring (TPM) system concerns.
00-00-90-002M2023-02-08. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; WHEELS; TIRES. This service bulletin provides information for accurate tire pressures that ensure the safe handling and appropriate ride characteristics of GM cars and trucks.
21-NA-2812023-02-08. Service bulletin. POWER TRAIN. This service bulletin provides diagnostic information for technicians in cases of an ETRS system fault or a no start condition - If the vehicle needs to be moved, it is recommended to use wheel dollies, tire skates or the NEW Manual Park Release tool DT-52910.
22-NA-2322023-02-08. Service bulletin. POWER TRAIN. This informational bulletin advises the technician of a possibly noise coming from the transmission oil pump.
22-NA-1132023-02-07. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This service bulletin provides repair information to correct a customer concern of Head Up Display (HUD) Blank, Non-Responsive to Brightness, Aim, or Page Controls, DTC U0158 Set.
21-NA-2442023-02-07. Service bulletin. ELECTRICAL SYSTEM; ELECTRICAL SYSTEM:IGNITION:ANTI-THEFT:IMMOBILIZER/PROXIMITY:KEY/SENDER. This service bulletin provides a repair procedure to correct a customer concern of a No Fob detected message on Driver Information Center (DIC) and/or No Crank / No Start condition.

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