I have a 2003 Accord LX, 4 cyl, 159,000 miles, manual xmission. My key fob lock/unlock buttons stopped working. The key fob battery voltage measured at less than 2v but should have been 3v or more. I changed the battery but the buttons still didn't work. I came across a youtube video which says that one can reprogram the key by turning the key to on position in the ignition, pressing the lock/unlock button, then turning it to the off position and repeating this 4 times. On the 4th attempt, and audible lock/unlock sound will be heard and the reprogramming should have been complete. I tried this method but it didn't work for me. Then I retrieved the 2nd key. Again the remote functions didn't work nor did the attempt to reprogram work. What could be the issue?

 

The procedure is to turn key on, in 1-4 seconds hit the lock/unlock button pointing toward the driver's door switch. In 1-4 seconds, turn the key off. Repeat 3 more times and you should hear the doors lock/unlock. Hit the lock or unlock button one more time. Then point any other key fobs towards the switch to program within 10 seconds. They should lock/unlock the doors. Turn the key off to finish.

I wasn't sure if you hit the lock/unlock after turning the key back to on. If you did, then you'll have to troubleshoot the driver's door switch/MICU.

Per the shop manual for your car, the remote won't work if a door is not fully closed or a key is in the ignition switch.

 

Hi PAhonda, I'm hitting the lock/unlock each time after turning the key back to on. There's something you said confused me, namely, "hit the lock/unlock button pointing toward the driver's door switch". The key in the ignition will automatically point towards the driver's door switch. I'm hitting the lock/unlock button on the key in the ignition. I shut the door fully closed before starting this procedure.

 

I didn't realize your key has the incorporated fob. The instructions are likely for a fob that is not part of the key. My TSX has the same procedure and I programmed a key like yours without issue, so pointing towards the driver's door isn't an issue.

Look at the gauge cluster and see if it is showing all doors closed, because a bad door switch could cause your issue.

For narrowing things down, do the switches inside the car lock/unlock the doors? If your outside door handle has a key hole, can the key lock/unlock the car doors?

 

The gauge cluster shows all doors closed. The switches inside the car do lock/unlock doors. All the keys (2 with remote and 1 valet key) can lock/unlock the doors and are also able to start the engine. I tried the programming procedure once again, with no success.

 

The door multiplex unit is part of the driver's door master switch and receives the signal from your key fob. The door multiplex unit sends a signal to the MICU to lock/unlock the doors.

Since the door master switch can send signal to the MICU by physically pushing buttons, I'll guess that you need to replace the door master switch.

 

I have ordered an after-market door master switch by SwitchDoctor. It cost around $37 as compared to Honda manufactured part for over $300!

 

Ok, so I received the new door master switch. I took the wiring connector off the old switch and plugged it into the new switch (see attached pic). Notice that I didn't remove the old switch completely so that I could test the new switch. I was able to program the automatic window up/down control. However, I still can't reprogram the key fob. One thing I noticed was the part number written on the old switch is SDA-A0 and the part number of the new switch is SDA-H1. I don't know if this is the issue. What should be my next step?

 

I returned the after-market switch with the wrong part number and bought another one (used) from eBay. It shows exactly the same part number as the original. I installed it. I tried programming each of the master keys individually. Neither one worked! Now I'm at my wit's end. I'm not sure how to proceed at this point.

 

Try to reset the transmitter by pressing the transmitter lock or unlock button 5 or 6 times.

It may take several tries for it to reset.