Keypad and Remote Door Open Problem
 

I replaced the original battery on my 2002 Mecury Mountaineer. Since then my keyless Entry Keypad doesn't work. I tried to reprogram using the Factory Default Code, but that doesn't work either. The Keypad will lock the doors, but that doesn't require a code. I believe the Factory Code is the same one as I used when the vehicle was new.

Also I can only program one Remote Door Lock. I can program the first one, but if I try to program another, neither will work. I have to disconnect the battery and start all over with programming.

Any help?

The Keypad doesn't illuminate when I try to enter the Default Code.

Maybe the keypad or Security Module got fubar when battery changed, or wiring issue between the two just coincided with battery change. I would look at the wiring since it doesn't cost anything. Most likely place to look for damage is in the rubber boot between the driver's door and the body. You really have to look closely at the harness in there because there is a bunch of wires in it.

If you don't see anything obvious come back and I'll look in my 2002/2003 wiring diagrams for connector pinouts for you.

I'll look at the wiring, but the Keypad will lock the doors when the two bottom keys are pressed.

Where is the Security Module?

How can I reset it?

The Security Module is located on the lower part of the passenger side 'C' pillar. You can pull the upper trim panel off and let it slide down the shoulder strap then pry the lower trim panel out enough to see the module. It will have the 5 digit factory security code printed on the label. I don't think there is a reset on it though.

I checked the wiring to the door, it looks OK.

When I push any button on the Keypad, the light under the Side mirrors lights and goes off after about 30 seconds. I tried each key, and all are the same. I think that the Keypad is OK, but the Default Code on the card is wrong.

I bought this vehicle new 7 years ago, and programmed it with a User's code. I must have had the right Default Code at that time.

I'll try to find the Security Module, and look at the code on the label

I found the Security Module, and the code is the same one that I have been using. it seems like the code got jumbled, or the Module has a problem.

I have an OBDII reader, and can reset codes. I don't think that I can get to the Security Module.

The dealer wants $149.00 to run the diagnostic program. There is no gaurantee that the problem can be fixed with a reprogram.
I can buy a used Body Computer from a similar wrecked vehicle for $50.00.
My question is:
Can I swap the BCU with another unit without confusing the other Computers?

I ran an OBDII scan, and reset one code for low EGR differential pressure. I replaced that sensor once already. Anyone familiar with that problem?

Keypad Problem
 

Did you ever find out how to fix this? I have a 2002 Explorer and I'm having the same problem. I replaced the battery and now the keypad won't open the door. I never programmed my own code so I've always just used the factory code. Now that doesn't work. I can lock the truck with the 0/9,7/8 buttons but when I enter the code to unlock nothing happens. My key fobs work too.

I also had the EGR sensor problem. I actually had a letter from Ford on that where they extended the warranty for that part by 2 years, 24K miles. But I was beyond that when mine failed. It was pretty easy to replace on the Explorer.

I never got it fixed. I think that the Security Module on the passenger side door post needed to be reprogrammed or replaced.

I sold the vehicle.