2023 Cadillac CT5 Problems: 12 Known Issues

On the 2022-2024 Cadillac CT5 6.2L Supercharged V8 (LT4), the 6.2L supercharged LT4 V8 in CT5-V Blackwing models has experienced premature engine failures including bottom-end bearing failures, lifter collapse, and metal shavings found in oil. Failures have been reported as early as about 1,800-3,100 miles. Car and Driver documented a catastrophic engine failure on their long-term test CT5-V Blackwing. GM initially claimed it was an isolated incident but forum reports suggest the problem is more widespread than acknowledged.

On the 2020-2025 Cadillac CT5 2.0L Turbo I4 (LSY), owners of four-cylinder CT5 350T (and CT4-shared LSY platform) models report higher-than-expected oil consumption, often exceeding GM's 'acceptable' threshold of one quart per ~2,000 miles. The valve-cover-integrated PCV system is a frequent contributor, and on worse cases worn piston rings or turbo seals allow oil into the combustion chamber. Symptoms commonly appear between 40,000 and 80,000 miles and are accompanied by low-oil warnings between changes, a lit check-engine light, and sometimes boost/lean codes. On some service variants the PCV diaphragm is built into the valve cover, so a failed PCV requires valve-cover replacement; other variants use a standalone PCV valve.

On the 2020-2024 Cadillac CT5 LSY, the 2.0T turbocharged four-cylinder (LSY) in the CT5 can develop oil leaks at the front of the engine. GM bulletin 21-NA-240 attributes this to an improper amount of sealant used on the cam carrier gasket at the front T-joint; the leak can look like it is coming from the timing (engine front) cover, camshaft carrier, lower oil pan or timing chain upper cover. In some cases, this leads to noticeable oil consumption between changes. Using incorrect oil viscosity can worsen the problem.

On the 2020-2023 Cadillac CT5, on certain 2020-2023 Cadillac CT5 vehicles, the daytime running lights may not deactivate when the headlights are on, creating excess glare and failing FMVSS 108.

On the 2020-2024 Cadillac CT5, a common cosmetic defect on 2020-2024 CT5 models: the gloss-black exterior B-pillar appliqués and window-surround trim bubble, haze, and delaminate, with the clear top layer lifting and flaking to expose a dull layer beneath. Owners describe small bubbles or a milky look first, progressing to peeling. The root cause is a manufacturing defect in the trim's adhesive/finish layers rather than owner abuse, and it affects multiple body panels around the side glass.

On the 2022-2024 Cadillac CT5 6.2L Supercharged V8, cT5-V Blackwing models equipped with the Tremec TR-6060 6-speed manual transmission frequently exhibit difficulty and notchiness when shifting into 2nd gear. The issue occurs both when cold and when hot, particularly when downshifting from highway speeds. Some dealers have attributed this to worn synchros requiring complete transmission replacement, while others consider a degree of notchiness normal for the Tremec unit. The problem varies in severity from mildly annoying to preventing clean shifts.

On the 2020-2025 Cadillac CT5, the CT5 uses GM's 10-speed automatic (10L80) that can exhibit harsh shifts, delayed engagement, and shift hunting, particularly when the adaptive learning resets. The 10-speed has very complex shift logic and can take 500+ miles to fully adapt to a driver's pattern after a battery disconnect, TCM update, or reset. Some CT5 owners report persistent shift quality issues even after adaptation. The CT5-V and CT5-V Blackwing have refined calibrations but can still exhibit occasional harsh shifts.

On the 2020-2024 Cadillac CT5, owners of sunroof-equipped CT5 models report creaking and rattling from the roof/sunroof and headliner area, especially over bumps and at speed. GM has no CT5-specific sunroof-creak bulletin; its roof-noise bulletin 19-NA-096 applies to the 2019 CT6, not the CT5. Forum members also trace noise to plastic-to-plastic contact at the sunroof trim ring and to loose interior trim near the headliner.

On the 2020-2024 Cadillac CT5, cT5 owners report a persistent whistle or high-pitched 'tone' (described as ringing in the ears) at highway speeds, typically 65 mph and up, plus buzzing from the door/window/headliner area at 50+ mph. Sources isolated by owners and dealers include the windshield weatherstrip lifting where it splits at the center, gaps in door weatherstripping, and even loose interior door-panel labels/tape flapping in the airstream behind trim.

On the 2020-2025 Cadillac CT5, owners report the 12V battery going dead when the car sits, with factory batteries dying in as little as two years. Beyond normal high parasitic draw of modern electronics, a recurring GM culprit is the driver-seat control module / Memory Seat Module (MSM), which can develop a several-amp draw that flattens the battery overnight; GM has revised these modules multiple times. Audio/amp circuits, the BCM, and sticking door/window switches are other documented draw sources on GM platforms.

On the 2020-2025 Cadillac CT5, a widely reported CT5 interior failure: the driver-seat massage and adjustable lumbar/bolster functions stop working. Dealers diagnose this as a failed seat 'module' — an all-in-one air-pump, valve and electronics unit feeding the seat air bladders. Owners report the failure at roughly 17,000 to 33,000 miles, and some have waited months for the part. Both standard and Recaro/performance seats are affected.

On the 2020-2025 Cadillac CT5, cT5 and CT5-V owners (and especially CT5-V Blackwing buyers with the optional Brembo carbon-ceramic package) report loud brake squeal, and at low speed a grindy or metal-on-metal sound, sometimes as early as ~5,000 miles. The copper-free friction-material formulation now mandated, combined with the aggressive performance pad compounds, makes the brakes noisy particularly in warm weather and at low speed. This is a comfort/noise issue rather than a stopping-performance defect, but Blackwing carbon-ceramic rotor replacement is extremely expensive if components are damaged.