2023 Cadillac CT4 Problems: 6 Known Issues

On the 2020-2023 Cadillac CT4, on certain 2020-2023 Cadillac CT4 vehicles, the daytime running lights may not deactivate when the headlights are on, creating excess glare and failing FMVSS 108.

On the 2022-2025 Cadillac CT4 LF4 3.6L Twin-Turbo V6, cT4-V Blackwing owners report a rhythmic squeak, chirp or squelching noise that rises in frequency with engine speed, most noticeable pulling away from a stop or under light throttle at low RPM and generally worse once the engine is fully warm. The noise is engine-speed related rather than road-speed related, so it is not a brake or wheel bearing issue. Owners and dealers have chased it to several sources on the LF4 3.6L twin-turbo: turbocharger wastegate actuators and their linkages, loose charge-air (boost) pipe clamps, turbo bearing noise, throttle body operation, and in some reports the high-pressure fuel pump drive. Several cars have had turbochargers replaced under warranty and the noise resolved.

On the 2020-2025 Cadillac CT4 LSY 2.0L Turbo I4, on the 2.0L turbo LSY four-cylinder used in the CT4 base/Luxury/Premium Luxury/Sport, oil weeps from what appears to be several places at once — the camshaft carrier cover, the engine front cover, the timing chain upper cover, and the lower oil pan. GM's own bulletin traces most of these to an improper amount of RTV sealant applied to the cam carrier cover gasket during engine assembly, so the leak is a manufacturing defect rather than normal gasket aging. Oil migrates down the front of the block and drips onto the subframe and exhaust, producing a burning-oil smell and low-oil messages between changes. Owners of both the CT4 and its LSY-engined sibling XT4 report the same leak, often re-appearing after a first repair attempt if the mating surfaces were not fully cleaned.

On the 2020-2025 Cadillac CT4 LSY 2.0L Turbo I4, the LSY 2.0L turbo routes crankcase vapors through a PCV/crankcase pressure sensor mounted in the valve cover area. In cold climates and on short-trip driving, water vapor condenses in the sensor port and hose and then freezes, blocking the reference passage. The ECM sees an implausible crankcase pressure signal and sets P04FB (Crankcase Ventilation Hose Connection Sensor Range/Performance), lighting the check engine light. Because the ice thaws once the car sits in a warm shop, dealers frequently find 'no problem found' and simply clear the code, and some replace the sensor unnecessarily. GM addressed it in a preliminary information bulletin covering CT4 and other LSY-equipped vehicles.

On the 2022-2025 Cadillac CT4 LF4 3.6L Twin-Turbo V6, cT4-V Blackwing cars ordered with the six-speed manual use a Tremec TR-6060. Owners consistently report that second gear is high-effort, notchy or outright baulks during the first few upshifts after a cold start, and in colder climates it can be difficult to select second at all until the gearbox reaches temperature. The high-temperature-capable manual transmission fluid GM specifies is very viscous when cold, which loads the second-gear synchro and slows synchronization. Most cars improve once warm and this is within the character of the TR-6060, but a subset of owners report second gear that stays notchy or grinds when hot, which is not normal and indicates genuine synchro or blocker-ring wear — some cars have had synchros or complete transmissions replaced under warranty.

On the 2020-2024 Cadillac CT4, cT4 owners across trims report a distinct pop, thump or creak from one or both front corners when crossing driveway dips, manhole covers, speed bumps, or during sharp low-speed steering maneuvers. The Alpha 2 front suspension uses a double-pivot strut arrangement, and the noise has been traced by owners and dealers to individual defective front struts — in several cases the strut body was found wet with damper fluid — as well as to strut mount and bushing seating. GM has circulated engineering-information requests asking technicians to complete a checklist when a popping or thump-type noise is heard from the front suspension during sharp maneuvers, which indicates GM is collecting field data on a recognized pattern rather than treating each car as a one-off. Many owners are told nothing is wrong on the first visit even when the technician can hear the noise.