One problem related to wiring has been reported for the 2009 Honda Odyssey. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2009 Honda Odyssey based on all problems reported for the 2009 Odyssey.
Took the car to the Honda dealership for emissions check light. Diagnosed as "nox sensor wiring harness chewed by mouse" per Honda dealership. There is no evidence of rodent damage or presence elsewhere in the vehicle. The Honda dealership did not provide me the pictures or the damaged part saying that it was thrown in the trash. The wiring was apparently covered by Honda rodent deterrent tape. I have contacted Acura/Honda dealerships, their extended warranty customer service and also the respective Acura/Honda manufacturer customer service. The same thing happened to my other car (Acura mdx 2009) within a span of one week with exactly similar presentation. When I requested information from the above sources, I was told that this was confidential information and is not available for customers and that is it is a rare event and not related to manufacturing defects and also there was no definitive trend in Acura/Honda(same company) nox sensor wiring harness being chewed by rodents and have refused to cover it under extended warranty program to which I have subscribed/purchased. I have another entry regarding the other vehicle at the NHTSA. Gov website.