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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

Only bulletins with component: Driver assistance are shown. Show all

Bulletins, newest first
PIT5698B2021-09-13. Service bulletin. ELECTRICAL SYSTEM:ADAS:BLINDSPOT:SENSORS. This Preliminary information communicates additional information on how a LIN bus operates and diagnostic tips when working on a LIN bus.
PIT5782C2021-05-17. Service bulletin. ELECTRICAL SYSTEM; BACK OVER PREVENTION. This Preliminary information communicates and issue with programming a replacement side object detection module and engineering is working on the issue.
21NA0802021-05-10. Service bulletin. BACK OVER PREVENTION. This service bulletin provides repair information to correct a customer concern of Flutter Type Noise Heard When Vehicle is Operating in AFM Mode (ECO Lamp On).
PIT5791A2021-04-19. Service bulletin. EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.; BACK OVER PREVENTION:SOFTWARE. This Preliminary information communicates a condition where the radio may display a :connection not availale, please call OnStar agent". This bulletin advises that Engineering is working on a software solution that will prevent the message from displaying when listening to non-SXM sources, but still allow the message to display when a loss of connectivity exists and the user is attempting to play Sirius XM.
N2023205102021-02-16. Service bulletin. LANE DEPARTURE; FUEL SYSTEM, GASOLINE; SERVICE BRAKES, HYDRAULIC; ELECTRICAL SYSTEM; AIR BAGS; ENGINE AND ENGINE COOLING; POWER TRAIN. Customer Satisfaction Program. Certain vehicles, equipped with a gas engine, may have a condition in which the printed circuit board inside of the water pump may have been manufactured incorrectly potentially causing a water pump failure. The vehicle coolant system temperature is monitored and will display multiple warnings to the customer as coolant temperatures rise. At a set coolant temperature, the MIL will illuminate, DTC P2B85 will set in the engine control module (ECM), the oil pressure gauge will indicate high oil pressure and reduced torque with notification to the driver of reduced power will occur. If the customer continues to drive after this warning and the coolant temperature continues to rise, a chime will occur, the AC will be disabled and an additional message instructing the driver to idle will illuminate. If the customer continues to drive the vehicle after all previous warnings and the coolant temperature continues to rise a message the engine will shut down could occur, and the engine will be shut down. Dealers are to replace the water pump.

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