My key does not seem to open locks or the trunk. Initially I thought the battery was dead/dying but replacing it did not work. I took it to a local shop where the person told me that some kind of a sensor in the car (not the key) was broken and needed to be replaced at a cost of $200. I am hoping someone here can guide me.

2005 Accord LX 4 cylinder sedan.

 

the transmitters may need to be reprogrammed. or your multiplex unit has gone south.

Transmitter Programming

Storing transmitter codes:
The codes of up to three transmitters can be stored into the keyless receiver unit memory. (If a fourth code is stored, the code which was input first will be erased.)

NOTE: It is important to maintain the time limits between the steps. Make sure the doors, the hood and the tailgate are closed.

1. Turn the ignition switch ON (II).
2. Within 1 to 4 sec , press the transmitter lock or unlock button with the transmitter aimed at the keyless receiver in the power window master switch.
3. Within 1 to 4 sec , turn the ignition switch OFF.
4. Within 1 to 4 sec , turn the ignition switch ON (II).
5. Within 1 to 4 sec , press the transmitter lock or unlock button with the transmitter aimed at the keyless receiver in the power window master switch.
6. Within 1 to 4 sec , turn the ignition switch OFF.
7. Within 1 to 4 sec , turn the ignition switch ON (II).
8. Within 1 to 4 sec , press the transmitter lock or unlock button with the transmitter aimed at the keyless receiver in the power window master switch.
9. Within 1 to 4 sec , turn the ignition switch OFF.
10. Within 4 sec , turn the ignition switch ON (II).
11. Within 1 to 4 sec , press the transmitter lock or unlock button with the transmitter aimed at the keyless receiver in the power window master switch.
12. Confirm you can hear the sound of the door lock actuators within 1 to 4 sec , then push the transmitter lock or unlock button again, or the code will not be stored.
13. Within 10 sec , aim the transmitters (up to two additional ones) whose codes you want to store at the keyless receiver, and press the transmitter lock or unlock buttons. Confirm that you can hear the sound of the door lock actuators after each transmitter code is stored.
14. Turn the ignition switch OFF, and pull out the key.
15. Confirm proper operation with the transmitters.

 

Thanks.

My remote starter seems to open and close doors remotely without any issues (it has the open/close buttons). It is a third party product and it was installed well after the problem with the keys occurred.

Will reprogramming keys have any affect on remote starter?

Lastly, where is this multiplex located? I've read about a driver side multiplex, one on passenger side, then another for windows, and one in the steering wheel.

 

if the remote does not work and you have a fresh battery, it could be the remote key innards. The button contacts wear out.

maybe # 72147-SDA-A11 Module. $47 to replace the guts in the remote.