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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: Software are shown. Show all

Bulletins, newest first
20-NA-1322024-04-05. Service bulletin. ELECTRICAL SYSTEM; ELECTRICAL SYSTEM:12V/24V/48V BATTERY; ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT. This warranty administration bulletin provides policy information on the requirements for 12V battery testing and warranty replacements.
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.
PIP5632G2023-01-30. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This Preliminary Information communication provides information to the technician that General Motors Technical Assistance Center may ask for Global Diagnostic System 2 Session Log. Technician will need use Global Diagnostic System 2 to send the session logs to General Motors Technical Assistance Center for further assistance on the vehicle in question.
PIP4902Q2023-01-30. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This Preliminary Information communication provides information to the technician that General Motors Technical Assistance Center may ask for Global Diagnostic System 2 Session Log. Technician will need use Global Diagnostic System 2 to send the session logs to General Motors Technical Assistance Center for further assistance on the vehicle in question.
PIT5832D2022-12-12. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. This Preliminary information communicates a diagnostic tip on how to resolve a issue if the serial data authentication configuration did not complete correctly.
PIT5832C2022-10-17. Service bulletin. UNKNOWN OR OTHER; ELECTRICAL SYSTEM:SOFTWARE; COMMUNICATIONS:BACK UP ALARM. This Preliminary information communicates a diagnostic tip on how to resolve a issue if the serial data authentication configuration did not complete correctly.
21NA2562022-02-14. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); EXTERIOR LIGHTING. This service bulletin provides repair information for dealers/technicians to correct a customer concern of a Malfunction Indicator Lamp Illuminated with DTC P26BB Set.
20NA1782021-12-27. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT; STEERING. This service 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 with DTCs U1614, U1615, U1616 Set.
20NA2382021-02-22. Service bulletin. EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.; ELECTRICAL SYSTEM:SOFTWARE. This service bulletin provides V153 radio software update information to correct customer concerns of various software issues.
20NA2372021-02-22. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.. This service bulletin provides V152 radio software update information to correct customer concerns of various software issues.
20NA2382021-02-01. Service bulletin. EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.; EQUIPMENT; ELECTRICAL SYSTEM:SOFTWARE. This service bulletin provides V153 radio software update information to correct customer concerns of various software issues.
20NA2372021-02-01. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.; EQUIPMENT. This service bulletin provides V152 radio software update information to correct customer concerns of various software issues.
16NA0192021-02-01. Service bulletin. POWER TRAIN; ELECTRICAL SYSTEM:SOFTWARE. This informational bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.

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