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Service bulletins for the 2021 Cadillac XT4

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.

684 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Only bulletins with component: Transmission and driveline are shown. Show all

Bulletins, newest first
PIC5650J2021-09-13. Service bulletin. POWER TRAIN; AIR BAGS. This Preliminary Information communication provides information to the technician about vehicles that have an intermittent no crank, no start, or start stall concern with the security light coming on. Technician may find Diagnostic Trouble Codes B3055, B3060, and/or B3935. Technician should not replace any parts for this concern. If unable to duplicate the concern ask if the customer uses any Radio Frequency Identification Devices when the concern is present. Dealer should also direct their customers to the appropriate section in the Owner manuals that references that the device complies.
990420002L2021-08-09. Service bulletin. POWER TRAIN:MANUAL TRANSMISSION; POWER TRAIN:AUTOMATIC TRANSMISSION; EQUIPMENT. This service bulletin provides information on Driveline Clunk Noise and what is acceptable and what is considered normal operation.
080730035E2021-08-09. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; POWER TRAIN. This bulletin provides information on the harmful effects of water or ethylene glycol in transmission fluid.
21NA0902021-07-19. Service bulletin. POWER TRAIN. This service bulletin provides a repair procedure to correct a customer concern of Whistle or Hoot/Woot Noise Heard from Under Vehicle in Cold Ambient Temperatures.
16NA3382021-05-24. Service bulletin. POWER TRAIN. This Warranty Admin service bulletin provides guidelines for Dealers Not Required and for Dealers Required to Contact the PQC for engine or transmission assembly replacement and explains the PQC process, GWM Transaction submission, vehicle service record retention and proper handling of assembly returns for Canadian Dealers only.
20NA1382021-05-03. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. This bulletin provides information on Policies Applicable to All U.S. Dealers for Engine and Transmission Assembly Replacement Under Warranty, Policy or Customer Enthusiasm and information on Submission of Warranty Transaction in Global Warranty Management.
PIP5712B2021-04-19. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:CRANK/CAMSHAFT POSITION SENSOR; POWER TRAIN. This Preliminary information communicates to the technician a service Diagnostic / Repair tip to avoid causing the crankshaft sprocket to disengage from the crankshaft during crankshaft balancer or cam drive system component related service procedures.
N2023193002021-03-22. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. Customer Satisfaction Program - Certain vehicles, equipped with a 9-speed automatic transmission, may contain transmissions that could shift harshly. Dealers are to replace the transmission.
N202321843 012021-03-22. Service bulletin. AIR BAGS; POWER TRAIN; EXTERIOR LIGHTING. Service Update. On certain vehicles equipped with automatic transmissions, the clutch spring retaining ring may not be fully seated. Vehicles with this condition may set DTC Code P0747 and the MIL light (malfunction indicator light) will illuminate. This typically occurs at low mileage. Dealers will inspect the transmission by following the procedure and if it fails, the transmission will be replaced.
150089004C2021-03-08. Service bulletin. SUSPENSION:FRONT:MACPHERSON STRUT; SUSPENSION:FRONT:SHOCK ABSORBER; POWER TRAIN:AUTOMATIC TRANSMISSION:FLUID/LUBRICANT. This service bulletin provides technicians with updated information to help identify the differences between what is considered a fluid leak, and what is considered fluid seepage.
16NA0192021-02-22. Service bulletin. POWER TRAIN. This informational bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
N2023193002021-02-16. Service bulletin. POWER TRAIN. Customer Satisfaction Program - certain vehicles equipped with a 9-speed automatic transmission may contain transmissions that could shift harshly. These transmissions must be replaced before sale and delivery to a customer. Parts are currently not available, but when parts are available, dealers will replace the transmission.
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.
060089031F2020-12-21. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; ENGINE. This service bulletin provides information on OEM and Remanufactured Engine and Automatic Transmission/Transaxle Identification.
1308116001F2020-12-07. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM; POWER TRAIN:AUTOMATIC TRANSMISSION. The intent of this technical bulletin is to identify aftermarket ALDL or DLC interface devices as potential sources for causing multiple customer concerns that do not have other diagnostic methods to identify them.
16NA0192020-10-26. Service bulletin. POWER TRAIN. This informational bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
16NA3612020-09-28. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. This informational bulletin explains possible normal condition of a flare from 1st to 2nd, even if the trans had been repaired for the flare and its still noticed.

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