The 2018 Cadillac CT6 is a mid-cycle full-size luxury sedan on GM's Omega platform. Powertrains include the 2.0L turbo (LTG), 3.6L NA V6 (LGX), and 3.0L twin-turbo V6 (LGW). Magnetic Ride Control is standard. The hand-built 4.2L Blackwing twin-turbo V8 arrived for 2019. Known issues: Magnetic Ride leaks, CUE durability, 2.0L LTG PCV failure.
A flagship sedan that mostly works well, but Magnetic Ride Control leaks and CUE touchscreen failures drag the ownership experience down. 3.0L TT V6 is the powertrain sweet spot.
MRC shocks develop leaks by 70K-110K mi. Premium dampers are expensive; some owners switch to conventional shocks at a fraction of the cost.
Run free diagnosis →CUE screens crack, delaminate, or stop responding to touch. Known durability problem; multiple TSBs and class-action discussions.
Run free diagnosis →PCV diaphragm in the cam cover fails, causing vacuum leaks and sudden oil consumption. Common GM Ecotec issue on the LTG.
View P0171 Diagnosis →GM 8L45 8-speed shudder at 30-45 mph light-throttle. Fluid flush with updated Dexron HP resolves many cases.
View P0700 Diagnosis →CT6's optional active rear-wheel steering can throw sensor faults and disable itself. Cosmetic when disabled but expensive to repair.
Run free diagnosis →Luxury electronics drain 12V battery if parked. Coded AGM replacement required.
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A heavily depreciated flagship - great value if you accept the maintenance reality. 3.0L TT V6 is the right engine. Pre-purchase check MRC for leaks and verify CUE touchscreen behavior.
Mid-cycle of a discontinued generation. Most software has settled but CUE and Mag Ride are intrinsic weak spots. Heavy depreciation makes it a value buy.
Expect $1,000-1,500/year in routine costs. Lifetime non-routine cost typically $4,000-8,000 to 120K miles, dominated by suspension and electronics.
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If your 2018 CT6 is throwing a check engine light, these are the codes most often associated with the problems above. Click any code for full diagnosis steps and typical repair costs.
About average. Drivetrain and chassis are solid; CUE infotainment and Magnetic Ride Control are the weak spots.
CUE infotainment touchscreen failures, followed by Magnetic Ride Control shock leaks.
3.0L TT V6 is the sweet spot - performance and (with 8L45 caveats) decent reliability. 2.0L LTG suffers PCV failures more often.
Several including airbag and electrical items. Always check NHTSA by VIN.
150,000-200,000 miles with disciplined maintenance. Electronics typically need attention well before mechanical death.
Yes - Cadillac ended CT6 production in 2020 in North America. Used market values are depressed as a result.