2025 Toyota Gr Corolla

The car showed a message that there is a system error and many warning lights came on, including the check engine light. Most of the warning lights indicated that many of the car's ADAS functions were disabled. The car also switched from AWD to FWD. The error code turned out to be P2C90 which relates to the PCV system. So, the car turned off all the safety features as a result of a minor emissions issue! Toyota has no repair for this; they just clear the code, ignoring completely that the safety features are turned off until the error is cleared.

Hello, Today (01/21/2026), on my 2025 Toyota GR Corolla vehicle (odometer 5243 miles), after 3200 miles of driving with the updated engine control unit (ECU) as of 10/14/2025 according to the T-SB-0071-25, a P2C90 error appeared again with an Check Engine Light. This happened during acceleration while entering the highway, when the engine speed reached between 3000 and 4000 RPM. This situation disables many of the vehicle's active safety systems (all-wheel drive, vehicle stability control, traction control, adaptive cruise control, lane keeping assist, etc.), exposing owners to unwarranted safety risks due to unexplained fluctuations in the crankcase ventilation monitoring system of a new and otherwise healthy engine. How can we get Toyota to release a better ECU firmware update to fix this problem? Obviously, the previous fix was not effective enough. Regards!

The car randomly reports an Engine Malfunction which results in many warning lights indicating that certain systems are non-functional. These include (but are not limited to): - Forward collision warning - Automatic emergency braking - Cruise control - Basically, any driver assistance feature that requires external sensors is turned off Also, the rear wheel drive is turned off so the car only drives using the front wheels. On each successive drive, with the engine turned off in between, some of these systems start functioning again. After 3 or 4 such driving cycles all the systems come back on. The dealer detected error code P2C90 (P2C9000) which refers to the positive crankcase ventilation system. The ventilation system was inspected and nothing was found to require repair. Others have reported this issue: - the video here shows the dash warning indicators: [XXX] - this person had to use the lemon law to return the car to Toyota [XXX] It is crazy that an errant emissions error disables the safety assistance features of the car. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)