Key fobs not working

Tiny
MTNMAN1982
  • MEMBER
  • 2005 HONDA ACCORD
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 166,000 MILES
I replaced the battery in my key fob, and it still does not work. It occurred to me that the receiver is in the master door control cluster, which I also replaced. Is there any way to program the receiver?
Wednesday, September 4th, 2019 AT 9:53 AM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hello,

The battery can only go in one way. Here is how the alarm system works and how to program the remote with diagrams below:

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.

Security Alarm System

NOTE: This applies to EX and EXL.

The security alarm system is armed automatically after the doors, hood, and trunk are closed and locked. For the system to arm, the ignition switch must be off, the key must be removed, and the MICU must receive signals that the doors, hood, trunk are closed and locked. The alarm can be disarmed at any time by unlocking the driver's door with the key or pressing the UNLOCK button on the remote transmitter.

When everything is closed and locked, the only inputs that are grounded, and have 0 volts, are the driver's door lock knob switch (LOCK position), and the integrated audio-HVAC display module. In other words, all of the other switches are open, and have about 5 volts with system awake and 1 volts in sleep mode, including the key cylinder switches. The security indicator in the gauge control module begins to flash immediately after the vehicle is completely closed and locked, and 15 seconds later, the security system arms and the security indicator flashes on fora shorter amount of time than before. If the security indicator does not flash, the system is not arming. A beep sounds and parking lights flash to confirm the security alarm system is armed if the LOCK button is pressed a second time within 5 seconds.

If one of the switches is misadjusted or shorted internally, or there is a short in the circuit, the security system will not arm. As long as the control unit continues to receive a ground signal (0 volts), it senses that the vehicle is not closed and locked, and the system will not arm. A switch that is slightly misadjusted can cause the alarm to sound for no apparent reason. In this case, a significant change in outside air temperature, the vibration of a passing truck, or someone bumping into the vehicle could cause the alarm to sound. There is no glass breakage or motion detector feature.

If anything is opened or improperly unlocked after the system is armed, the control unit receives a ground signal from that switch, and the 1 - 5 volts reference drops to 0 volts. If the integrated audio-HVAC display module is disconnected, the input loses its ground, and the input voltage goes to 1 - 5 volts. The system sounds the alarm when any of these occur:
- A door or the trunk is forced open
- A door is unlocked without using the key or the remote transmitter
- The hood is opened
- The audio-HVAC display module is disconnected
- The remote panic is operated

When the system sounds the alarm, the horns sound and the exterior lights flash for 2 minutes. The alarm can be stopped at any time by unlocking the driver's door with the key or by pressing any button on the remote transmitter.

Panic Mode

The panic mode sounds the alarm in order to attract attention. When the PANIC button on the remote transmitter is pressed and held for 2 seconds, the alarm sounds and the exterior lights flash for about 20 seconds.

The panic mode can be cancelled at anytime by pressing any button on the remote transmitter or by turning the ignition switch ON (II). The panic mode will not function if the ignition switch is ON (II).

Keyless Entry System

The keyless entry system is integrated with the MICS. The multiplex integrated control unit (MICU) receives LOCK, UNLOCK and PANIC signals from the door multiplex control unit (keyless receiver).

The keyless entry system allows you to lock and unlock the vehicle with the remote transmitter. When you press the LOCK button, all doors lock. When you press the UNLOCK button once, only the driver's door unlocks. The other doors will unlock when you press the button a second time. The doors will not lock with the remote transmitter if a door is not fully closed, or if the key is in the ignition switch.

If the UNLOCK button is pressed, released, then pressed and held, the windows will begin to open. The windows stop if the button is released. See power windows for more information and troubleshooting.

When the switch for the ceiling light is in the center position, it will come on when the UNLOCK button is pressed. If a door is not opened, the light will go off in about 30 seconds, and the doors will relock. If the doors are locked with the remote transmitter within 30 seconds, the light will go off immediately.

Immobilizer Key Registration

NOTE:
- The HDS is required for registration of the immobilizer keys.
- Check for aftermarket electrical equipment that can cause problems with transponder operation.
- The immobilizer control unit-receiver can store up to six immobilizer Keys.

Add a new key

1. Have a registered key, a new immobilizer key, and the first pass word from the IN system.
2. Connect the HDS to the data link connector.
3. Turn the ignition switch ON (II).
4. Select "IMMOBILIZER" from the "SYSTEM SELECT" menu.
5. Select "Keys", then "Add 1 key".
6. Do the registration according to the instruction of HDS screen.
7. Check if the engine can be started by the newly registered key.

Add new keys

1. Have a registered key, all new keys, and the immobilizer PCM code.
2. Connect the HDS to the data link connector.
3. Turn the ignition switch ON (II).
4. Select "IMMOBILIZER" from the "SYSTEM SELECT" menu.
5. Select "Add and Delete Keys", or "Delete or Add Multiple Keys".
6. Do the registration according to the instruction of HDS screen.
7. Check if the engine can be started by all the registered keys.

Replace any of the keys

NOTE: If any of the registered keys were lost, do the following procedure to delete the lost registered key.

1. Have at least one original key, all other keys to be registered and the immobilizer PCM code.
2. Connect the HDS to the data link connector.
3. Turn the ignition switch ON (II).
4. Select "IMMOBILIZER" from the "SYSTEM SELECT".
5. Select "KEYS", then "REWRITE KEYS".
6. Do the registration according to the instruction of HDS screen.
7. Check if the engine can be started by all the registered keys.

All keys are lost

1. Prepare all new keys and have the immobilizer PCM code.
2. Connect the HDS to the data link connector.
3. Turn the ignition switch ON (II).
4. Select "IMMOBILIZER" from the "SYSTEM SELECT" menu.
5. Select "KEYS", then "ALL KEYS LOST".
6. Do the registration according to the instruction of HDS screen.
7. Check if the engine can be started by all the registered keys.

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Thursday, September 5th, 2019 AT 2:27 PM
Tiny
MTNMAN1982
  • MEMBER
  • 3 POSTS
I still cannot get 2 original keys or two new keys to operate the door locks remotely after following all programming instructions. I have not yet taken the new keys to a locksmith, nor have I tried to do anything about the immobilizer until I get the transmitters working. You supplied drawings and instructions at the end of the post for removing and replacing the Immobilizer Control Unit in the steering column. I am confused about whether this indeed needs to be replaced since my original keys start the car. I am also confused about what and where the referenced MICU (Multiplex integrated control unit) and the Door Multiplex control unit (keyless receiver) are located and what they do. These items seem to be a part of my issue. As I originally mentioned, I replaced the master window/lock control unit in the driver side door some time ago and do not have the original unit any longer (and looking back, that's when everything stopped working)
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Monday, September 9th, 2019 AT 10:32 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Both the MICU (Multiplex integrated control unit) and the Door Multiplex control unit (key-less receiver) work in the CAN system we need to run a scan to see which one is bad. here is a video of the job being done:

https://youtu.be/InIlnsjOVFA

Lets check fuses 8,7 and 21.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here are the security system wiring diagrams so you can see how the system works with the fuse and security system component locations. Check out the diagrams (below). Please let us know what you find.
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Monday, September 9th, 2019 AT 11:16 AM
Tiny
MTNMAN1982
  • MEMBER
  • 3 POSTS
I actually took the master door unit out and checked all connections. When I re-installed it, I was able to get the keys to go into program mode and got them programmed! For some reason, I believe the built in antenna was not recognizing the signal from the remotes. Now I need to get the new keys cut and get the immobilizer to recognize them. Thanks!
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Monday, September 9th, 2019 AT 2:09 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Could have been a bad connection at the connector. Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Tuesday, September 10th, 2019 AT 10:46 AM

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