P0742 on Cadillac
Torque Converter Clutch Circuit Stuck On
P0742 on Cadillac vehicles indicates torque converter clutch circuit stuck on. Au7o has documented this code across 3 Cadillac models — most commonly on CT5, Escalade, XT5. P0742 means the torque converter clutch (TCC) circuit is stuck on, meaning the lockup clutch that mechanically links the engine to the transmission stays engaged when it should release. The computer commands the clutch on and off, and when it detects the converter clutch remaining applied, it sets this code. The classic symptom is the engine stalling when coming to a stop, similar to driving a manual without pushing the clutch in, along with possible harsh shifts or poor fuel economy. It points to a hydraulic or solenoid problem inside the transmission rather than the engine. Typical repair costs on Cadillac range from $200 to $4,500, depending on the specific model and root cause.
Common Causes of P0742
- •Stuck or failed torque converter clutch solenoid
- •Stuck valve in the valve body (TCC apply valve)
- •Contaminated or degraded transmission fluid
- •Internal transmission hydraulic leak holding the clutch on
- •Wiring or connector fault to the TCC solenoid
- •Faulty torque converter
- •Dirty or clogged transmission filter
P0742 on Cadillac by Model
Cadillac CT5(1 issue)
- 10-Speed Transmission Adaptive Learning and Shift Quality2020-2025
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.
Cadillac Escalade(2 issues)
- 10L80 Transmission Harsh Shifting and Shudder2021-2025
The 5th generation Escalade (2021+) uses the GM 10L80 10-speed automatic transmission. While improved over the 8L90, some owners report harsh shifting, shudder at light throttle, and delayed shifts. The 10-speed has numerous clutch packs and a complex valve body with frequent adaptive learning resets needed. Some units develop torque converter shudder similar to the 8L90 issue. GM has released multiple TCM software updates to address shift quality. The issue is less prevalent than the 8L90 but still documented.
- 8L90 Transmission Shudder and Harsh Shifting2015-2020
The 2015-2020 Escalade uses the GM 8L90 8-speed automatic transmission that suffers from a widespread torque converter shudder issue. The shudder typically occurs at light throttle between 25-50 mph and feels like driving over rumble strips. The root cause is the torque converter clutch wearing prematurely, contaminating the transmission fluid with clutch material. GM extended the warranty and released updated torque converters and fluid, but many owners still experience the issue after the fix. This was the subject of a class action lawsuit.
Cadillac XT5(1 issue)
- 8-Speed / 9-Speed Transmission Shudder and Harsh Shifting2017-2025
The Cadillac XT5 uses an 8-speed (2017-2019) or 9-speed (2020+) automatic transmission. The 8-speed shares the torque converter shudder issue with other GM 8-speed vehicles. The 9-speed (GM 9T50/9T65) can have harsh shifts, delayed engagement, and shift hunting. Both transmissions have been subject to multiple software calibration updates from GM. The 9-speed is particularly sensitive to fluid condition and requires proper Dexron HP fluid.
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View P0742 across all makes →Frequently Asked Questions
What does P0742 mean on Cadillac?▼
P0742 stands for "Torque Converter Clutch Circuit Stuck On." P0742 means the torque converter clutch (TCC) circuit is stuck on, meaning the lockup clutch that mechanically links the engine to the transmission stays engaged when it should release. The computer commands the clutch on and off, and when it detects the converter clutch remaining applied, it sets this code. The classic symptom is the engine stalling when coming to a stop, similar to driving a manual without pushing the clutch in, along with possible harsh shifts or poor fuel economy. It points to a hydraulic or solenoid problem inside the transmission rather than the engine. On Cadillac specifically, this code is documented across 3 models.
What causes P0742 on Cadillac vehicles?▼
Common causes on Cadillac: Stuck or failed torque converter clutch solenoid, Stuck valve in the valve body (TCC apply valve), Contaminated or degraded transmission fluid, Internal transmission hydraulic leak holding the clutch on, Wiring or connector fault to the TCC solenoid. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0742 on a Cadillac?▼
Repair costs on Cadillac range from $200 to $4,500, depending on the specific model and root cause.
Which Cadillac models have P0742 documented?▼
Au7o has documented P0742 on 3 Cadillac models: CT5, Escalade, XT5.