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Service bulletins for the 2018 Cadillac CT6

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.

1096 on file from NHTSA, as of 2026-10-19.

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Only bulletins with component: Electrical system are shown. Show all

Bulletins, newest first
PIC64502022-03-14. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a process to correct the concern of Unable to contact OnStar after the 3G EOL on 2015-2022 model year vehicles in the United States.
PIT5745C2022-03-14. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates and issue with the memory seat module waking up the low speed GM lan bus and causing a battery draw.
PIC6048N2022-02-14. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN; STEERING; AIR BAGS; LANE DEPARTURE; BACK OVER PREVENTION. This Preliminary Information communicates to the technician that some customers may comment on the operation of their haptic seat during a Lane Keep Assist event. Lane Keep Assist works differently than Lane Departure Warning. The Lane Keep Assist icon is solid amber, Forward Camera Module is actively commanding a torque to Electronic Power Steering. This means that the driver should also feel some feedback from the steering wheel. No Chimes or haptic in the seat. Lane Keep Assist icon is flashing amber; Forward Camera Module is actively commanding torque to Electronic Power Steering. This will also be accompanied with Lane Departure Warning chimes and haptic in the seat feedback based on the setting chosen in the vehicle settings. This will take place when the vehicle has crossed lane marking by (40 cm) or (15.75 in).
18239012022-02-14. Service bulletin. ELECTRICAL SYSTEM; AIR BAGS; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); EXTERIOR LIGHTING. Emissions Recall. General Motors has decided to conduct a Voluntary Emission Recall involving certain vehicles, equipped with 4-cylinder engines (RPO LHN, LEX, L3A, LYX, LKN, LE2, LCV or LTG). On some vehicles, an electrical connection in the circuit board may fail in the engine control module. If this occurs, a malfunction indicator lamp (MIL), such as the Check Engine Light may illuminate. Replace the Engine Control Module (ECM).
18239 Dealer Mes2022-02-07. Service bulletin. ELECTRICAL SYSTEM. Emission Recall. Customer Mailing completed September 4, 2018.
18165 022022-02-07. Service bulletin. ELECTRICAL SYSTEM; VEHICLE SPEED CONTROL. Customer Satisfaction Program. All vehicles equipped with Hands-Free Lane Following (UKL) require control software improvement to optimize the performance of the Super Cruise system. Reprogram the long-range radar and active safety control modules.
18165 012022-02-07. Service bulletin. ELECTRICAL SYSTEM; VEHICLE SPEED CONTROL. Customer Satisfaction Program. All vehicles equipped with Hands-Free Lane Following (UKL) require control software improvement to optimize the performance of the Super Cruise system. Reprogram the long-range radar and active safety control modules.
181652022-02-07. Service bulletin. VEHICLE SPEED CONTROL; ELECTRICAL SYSTEM. Customer Satisfaction Program. All vehicles equipped with Hands-Free Lane Following (UKL) require control software improvement to optimize the performance of the Super Cruise system. Reprogram the long-range radar and active safety control modules.
18239 012022-02-07. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); ELECTRICAL SYSTEM. Emissions Recall. General Motors has decided to conduct a Voluntary Emission Recall involving certain vehicles, equipped with 4-cylinder engines (RPO LHN, LEX, L3A, LYX, LKN, LE2, LCV or LTG). On some vehicles, an electrical connection in the circuit board may fail in the engine control module. If this occurs, a malfunction indicator lamp (MIL), such as the Check Engine Light may illuminate. Replace the Engine Control Module (ECM).
21NA2782021-12-27. Service bulletin. ENGINE; ELECTRICAL SYSTEM. This service bulletin provides diagnostic strategy information to aid in diagnosing a Ticking, Tap or Rattle Noise from Engine with Possible Misfire, Malfunction Indicator Lamp (MIL) Illuminated.
20NA1322021-12-20. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY. This warranty administration bulletin provides policy information on the requirements for battery testing and warranty replacements.
PIC6265F2021-09-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates that a vehicle may exhibit a Adaptive Cruise Control Unavailable and/or Lane Keep Assist Unavailable message. The technician may attempt to program the Active Safety Control Module (ASCM) and encounter a code E4399. The technician is advised if he encounters this concern to zero the MIC counter by placing the vehicle into and back out of "Transport Mode".
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.
PIC5650J2021-09-13. Service bulletin. ELECTRICAL SYSTEM. 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.
N2023180002021-08-09. Service bulletin. ELECTRICAL SYSTEM:WIRING; EQUIPMENT; POWER TRAIN. Service Update. Certain vehicles may have a condition where the transmission wiring harness may have a faulty thermistor crimp. Dealers are to replace the transmission wiring harness.
21NA1472021-08-09. Service bulletin. ELECTRICAL SYSTEM:IGNITION:COIL:SPARK PLUGS; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE AND ENGINE COOLING. This service bulletin provides a repair procedure to correct a customer concern of Coolant and/or Oil Leak, Malfunction Indicator Lamp (MIL) Illuminated?.
21NA1392021-08-09. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM). This service bulletin provides a repair procedure to correct a customer concern of a Malfunction Indicator Lamp (MIL) Illuminated - DTC P3055 Set.
19NA0442021-07-19. Service bulletin. ELECTRICAL SYSTEM; ENGINE. This service bulletin provides information on the cold start control system in DI engines to reduce cold start emissions and improve fuel economy.
21NA1242021-07-06. Service bulletin. ELECTRICAL SYSTEM. This service bulletin provides diagnostic tips/steps on testing for possible EVAP leaks in the system to correct a customer concern of an MIL Illuminated with DTCs P0442 and/or P0455 Set.
20NA1322021-05-03. Service bulletin. ELECTRICAL SYSTEM. This warranty administration bulletin provides policy information on the requirements for battery testing and warranty replacements.
PIT5745B2021-04-19. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates and issue with the memory seat module waking up the low speed GM lan bus and causing a battery draw.
150603002H2021-04-16. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. Original Equipment Batteries Part Number and ACDelco Replacement Battery Approved Warranty Part Numbers Correct battery cold cranking amperage (CCA) ratings and type are critical for proper test results when using the EL-50313. Access to the battery specification label, which contains the OEM part number and CCA rating and type, may be difficult without component removal. Refer to the table below for the original equipment ratings and part numbers used to set up a proper battery test. There has been some confusion as to the correct ACDelco battery warranty replacement. Refer to the table below for the correct battery warranty replacement. The correct ACDelco battery warranty replacement in the catalog is designated by the "Original Equipment Replacement" note in the description field.
070849020M2021-04-16. Service bulletin. ELECTRICAL SYSTEM:INSTRUMENT PANEL:SPEEDOMETER/ODOMETER:SENSOR/SENDING UNIT; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. IPC Odometer Programming Method Quick Reference Guide
17-NA-3372021-04-15. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. All or Some Options May Be Missing from Driver Information Center (DIC) “Info Pages” Menu Due to Them Not Being Selected Condition Some customers may comment that with the “Info” option selected from the main menu (1), the “Info Pages” are blank (2) when scrolling up and down. If information is present when scrolling up and down, they may also comment that certain items are missing when compared to other like vehicles Cause This condition may be caused when all/some of the options not being selected in the “active info pages” menu. Correction If this concern is encountered, determine if all/any of the selections in the “active info pages” menu are not selected. To do this, follow the steps listed below.
17-NA-2922021-04-14. Service bulletin. ELECTRICAL SYSTEM:WIRING:RELAYS/SOLENOIDS; ELECTRICAL SYSTEM:WIRING. Malfunction Indicator Lamp (MIL) Illuminated - DTC P3409 and/or P3433 Condition Some customers may comment that the MIL is illuminated. The technician may find one or more of the following DTCs set: • P3409 • P3433 Cause This condition may be caused by a wiring issue with both/either the cylinder 2 deactivation solenoid oil control valve circuit and/or the cylinder 5 deactivation solenoid oil control valve circuit. These codes may be active or stored in history. • This may also be a repeat concern. Correction Note: When replacing the solenoids, ensure there are no terminal issues at the connector. To correct this condition, refer to the information below: • If vehicle was built between 4/13/2017 and 8/7/2017, it will be necessary to replace both right and left bank Cylinder Deactivation Solenoids (AFM OCV). • If vehicle was built outside the date range, check for any terminal issues at the connector. If no trouble found, follow SI diagnostics for the applicable DTC.

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