Automatic Transmission Control Module problems of the 2020 Honda Odyssey

Upon starting the vehicle, it failed to engage in reverse. Although the backup camera activated, the vehicle remained stationary. After multiple ignition cycles, the vehicle eventually engaged in reverse and then moved forward in drive. However, shortly after, the vehicle experienced a sudden loss of power and entered "limp mode," restricting speed to approximately 15–20 mph regardless of throttle input. The engine revved excessively high without corresponding acceleration, and a severe burning/heat smell emanated from the transmission/engine compartment. This failure occurred without any prior warning; notably, no dashboard warning lights or "check engine" indicators illuminated to alert the driver of a mechanical or electronic fault. The sudden, un-signaled drop in speed on a public roadway created a significant safety hazard for following traffic and risked a rear-end collision. The vehicle was towed to a certified Honda dealership where the transmission control module (tcm) was diagnosed as failed. The tcm is currently being replaced under the Honda certified pre-owned (cpo) warranty. We do not know what else requires replacement and repairs. The dealership will not cover the replacement of the transmission fluid, or engine fluid, despite the fluid being subjected to extreme heat and potential damage during the failure and subsequent limp mode.

At 67,000 miles the transmission was lurching when shifting in 4th gear. Took it to Honda dealership who found code p0736 stored in tcm. Transmission fluid flushed January 2024 by same dealer. No warning lights ever appeared. Body shop said this requires a new transmission at $10k+.