tldr; Your fob key battery may be fine, but your car battery may be dead.
My cousin from SF was visiting us over last weekend. They wanted us to keep their Honda Odyssey 2016 for a week when they went for their week-long Mexico cruise. Everything was good with the car for the first two days. On the third day, the car alarm went off apparently for no reason. I wasn't home at that time, and my wife unlocked and locked the car with the fob key and everything was good. Then two days later, I wanted to open the car to keep some bags inside. I was shocked to find the car not responding!
The small red LED light on the fob key was still turning on when I pressed the buttons, but the car simply didn't respond. My natural response was to think that something was wrong with the fob key. I noticed that my cousin's son had put some small toy magnets with the key and those were sticking on it. I suspected those magnets messed up something inside the fob key. I have never used a fob key and a keyless ignition so far, so had to google around. The first reason everyone mentioned was that the battery inside the fob key might be dead. Figured out how to open the fob key and change the battery, a CR2032 3 volts battery (costs $2 a piece at Walmart). I tried again, but still no response from the car! I was suspecting that would be the case since the car is brand new and the LED lamp was turning on when I pressed the buttons.
I did not realize that when I opened the fob key, the physical key that the fob key had inside it could actually open the car. (See this video if you don't know how to get the physical key out of the fob key.)
I thought the car doesn't have a slot for the physical key, but had I seen below the driver door handle, I would have seen the slot to insert the physical key and open the door! Alas, the way I had parked the car in a corner with little room to stand next to the driver side door hid that slot when I was standing.
I called couple of my friends who have Honda Odysseys and they were clueless too. Everyone was thinking of complicated reasons like the car having some anti-theft protection that locks the car automatically, etc., No one even suggested trying to open the car with the physical key and check if the car would start!
I finally ended up calling AAA. First they sent a lockout technician. Even he didn't know that the physical key could open the car. He did his usual stuff on the passenger window and opened the car. But he correctly guessed that the car battery might be dead. I got in, pressed the ignition button and there was no response. Then I called AAA again to get battery jump. This guy was the one who finally told me I could use the physical key to open the door! He gave a jump start and then we started looking why the battery died. One of the lamps inside was on! And it was the lamp next to where my cousin's five year old son sat! He had left the lamp on and since I drove the van only during the day, I never noticed it! I turned off all the lamps and then drove the car for half an hour for the battery to recharge. All good after that.
If you ever face this problem, then first open the car with the physical key and check if the car battery is alright.
My cousin from SF was visiting us over last weekend. They wanted us to keep their Honda Odyssey 2016 for a week when they went for their week-long Mexico cruise. Everything was good with the car for the first two days. On the third day, the car alarm went off apparently for no reason. I wasn't home at that time, and my wife unlocked and locked the car with the fob key and everything was good. Then two days later, I wanted to open the car to keep some bags inside. I was shocked to find the car not responding!
The small red LED light on the fob key was still turning on when I pressed the buttons, but the car simply didn't respond. My natural response was to think that something was wrong with the fob key. I noticed that my cousin's son had put some small toy magnets with the key and those were sticking on it. I suspected those magnets messed up something inside the fob key. I have never used a fob key and a keyless ignition so far, so had to google around. The first reason everyone mentioned was that the battery inside the fob key might be dead. Figured out how to open the fob key and change the battery, a CR2032 3 volts battery (costs $2 a piece at Walmart). I tried again, but still no response from the car! I was suspecting that would be the case since the car is brand new and the LED lamp was turning on when I pressed the buttons.
I did not realize that when I opened the fob key, the physical key that the fob key had inside it could actually open the car. (See this video if you don't know how to get the physical key out of the fob key.)
I thought the car doesn't have a slot for the physical key, but had I seen below the driver door handle, I would have seen the slot to insert the physical key and open the door! Alas, the way I had parked the car in a corner with little room to stand next to the driver side door hid that slot when I was standing.
I called couple of my friends who have Honda Odysseys and they were clueless too. Everyone was thinking of complicated reasons like the car having some anti-theft protection that locks the car automatically, etc., No one even suggested trying to open the car with the physical key and check if the car would start!
I finally ended up calling AAA. First they sent a lockout technician. Even he didn't know that the physical key could open the car. He did his usual stuff on the passenger window and opened the car. But he correctly guessed that the car battery might be dead. I got in, pressed the ignition button and there was no response. Then I called AAA again to get battery jump. This guy was the one who finally told me I could use the physical key to open the door! He gave a jump start and then we started looking why the battery died. One of the lamps inside was on! And it was the lamp next to where my cousin's five year old son sat! He had left the lamp on and since I drove the van only during the day, I never noticed it! I turned off all the lamps and then drove the car for half an hour for the battery to recharge. All good after that.
If you ever face this problem, then first open the car with the physical key and check if the car battery is alright.
