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
| PIP5712B | 2021-04-19. 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. |
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| PIC6433 | 2021-04-19. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM):SOFTWARE. This Preliminary information communicates that a service theft deterrent message may display with no DTC's. OnStar will turn of the ECM read request to prevent re-occurrence. |
| PIP5712A | 2021-04-19. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:CRANK/CAMSHAFT POSITION SENSOR. 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 removal. |
| PIT5817A | 2021-04-19. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates and issue with a SES MIL and the BCM keeping the ignition main relay on after the vehicle is turned off. Dealers are to replace the BCM. |
| PIP5784 | 2021-04-19. Service bulletin. STRUCTURE. This Preliminary information communicates to the dealer technician to inspect for a missing 1-2-7-8-R clutch fluid passage seal or incorrect 1-2-7-8-R clutch fluid passage seal being install for a no movement concern after valve body replacement on the 8L45 or 8L90 transmissions. |
| PIC6384D | 2021-04-19. Service bulletin. ELECTRICAL SYSTEM; STRUCTURE. This Preliminary information communicates a parts restriction is in place for the Body Control Module on 2020 Cadillac CT4, CT5, Chevrolet Corvette, Suburban, Tahoe and GMC Yukon. |
| PIE0606A | 2021-03-08. Service bulletin. AIR BAGS; ELECTRICAL SYSTEM. This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to the service airbag lamp illuminated on the driver information center (DIC). |
| 150089004C | 2021-03-08. 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. |
| 21NA026 | 2021-03-08. Service bulletin. EQUIPMENT; STRUCTURE; EQUIPMENT ADAPTIVE/MOBILITY. This service bulletin provides information for dealers/technicians on accessory all-weather floor liners and flat mats warped or misshapen. |
| 18NA285 | 2021-03-01. Service bulletin. EQUIPMENT; FUEL SYSTEM, OTHER:KINETIC:CLUTCH. This informational bulletin advises the tech of a possible normal condition when the vehicle creeps forward during start up conditions when the clutch packs are full of residual oil. |
| 18NA073 | 2021-03-01. Service bulletin. ENGINE. This service bulletin provides graphics, information and guidelines for engine component wear to assist service personnel as a guideline to perform necessary engine repairs and prevent unnecessary engine replacement. |
| PIE0606 | 2021-03-01. Service bulletin. ELECTRICAL SYSTEM; AIR BAGS. This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to the service airbag lamp illuminated on the driver information center (DIC). |
| 090604026S | 2021-03-01. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:GASOLINE; EQUIPMENT. This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2. |
| 040089015V | 2021-03-01. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin provides information on Warranty Administration ? Required Operating Procedures - 8 Points (U.S. Only). |
| 010601011L | 2021-03-01. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION; EQUIPMENT. This informational bulletin provides guidelines and diagnostic/repair information to technicians regarding vehicle engine oil consumption. |
| N202320510 | 2021-03-01. Service bulletin. AIR BAGS; ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM; FUEL SYSTEM, GASOLINE; EQUIPMENT. 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. |
| 20NA238 | 2021-02-22. 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. |
| 20NA237 | 2021-02-22. 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. |
| 20NA235 | 2021-02-22. Service bulletin. EQUIPMENT:APPLIANCE:TV/RADIO/SPEAKERS. This service bulletin provides information to aid a dealer/customer concern of Radio Unwanted Phantom Touch or Non-Responsive to Touch After Cleaning/Disinfecting Radio Display. |
| 20NA159 | 2021-02-22. Service bulletin. TIRES. This Warranty Administration bulletin is for information on General Motors New Vehicle Tire Warranty Program (U.S. Dealers Only). |
| 18NA306 | 2021-02-22. Service bulletin. EQUIPMENT. This Warranty Administration bulletin provides information for dealers/Service advisors on when and how to submit a Pre-Repair Authorization (PRA). |
| 16NA019 | 2021-02-22. Service bulletin. POWER TRAIN. This informational bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares. |
| N202320510 | 2021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. 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. |
| N202320510 | 2021-02-16. 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. |
| PIT5799A | 2021-02-16. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a cocnern where a flashing spot can intermittently show up on the radio display while in reverse. The PI advises that engineering is investigating the concern. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.