CTS Transmission Warning: Grinding & Limp Mode Alert

I had nearly identical symptoms with my 2013 Cadillac ATS with 95000km. The transmission warning and limp mode triggered after the transmission sensor started sending incorrect readings to the control unit. The root cause was a combination of low transmission fluid and a faulty pressure switch. The pressure gauge readings were inconsistent, which made the transmission control unit reduce power to prevent damage. The grinding during shifts typically indicates inadequate oil pressure or worn components struggling without proper lubrication. This turned out to be quite serious, low transmission fluid can cause permanent damage if not addressed quickly. The repair required: Replacement of the faulty transmission pressure switch, New transmission oil sensor, Complete transmission fluid flush, Recalibration of the transmission control module After fixing the sensor fault and restoring proper fluid levels, the transmission returned to smooth operation. Going too long without repair risks internal transmission damage that could require a full rebuild. The key is finding a shop with proper diagnostic equipment to accurately read transmission pressure and properly identify failing sensors. A transmission specialist would be better equipped than a general mechanic for this type of repair.

Thanks for sharing your experience. The symptoms you described match exactly what happened with mine. The transmission pressure switch replacement fixed the issue for me, along with the new sensor and fluid change. Since you mentioned repair details, do you remember roughly how much you paid for the complete fix? Also curious if youve had any other transmission issues pop up since getting it repaired?

After getting it fixed last month, my ATS transmission has been working flawlessly. The transmission fault warning hasnt returned since they replaced the faulty oil pressure sensor and corrected the oil level. The total repair came to 365€, which included parts and labor. This covered the new transmission oil pressure sensor, a complete fluid change, and diagnostic work. They found the gearbox oil level was too low, which was causing the grinding sounds during shifts. Looking back, getting it repaired quickly was the right call. Running a transmission with low fluid or bad sensors can lead to much more expensive damage. Monitoring the transmission oil level is now part of my regular maintenance routine to prevent similar issues.

Thanks for the feedback, everyone. I wanted to share how my repair went since many asked. Finally took my CTS to a transmission specialist who properly diagnosed the issue. The pressure switch and transmission sensor were indeed the culprits. They found the oil level was critically low, which explained the grinding. The whole repair took about 4 hours and cost 420€ total. This included: New transmission pressure switch, Oil level sensor replacement, Complete fluid change, Computer reset The transmission now shifts perfectly, no more warning lights or limp mode. They showed me the old parts, and the sensor fault was obvious from the corrosion. Really glad I got it fixed before causing more damage. For anyone with similar symptoms, definitely check your transmission oil level first and get it to a specialist if you notice any grinding. The cost of early repair is way better than a full transmission rebuild.