So the other day my key fob quit working on my 2000 SR5. I figured no problem, battery must have died. Put a new battery in the fob, no luck. Took it to autozone and tried their tester and it showed it was giving out a rf signal. A friend of mine said if I disconnect the vehicle battery at some time that will cause it to lose the programming. I don't buy into that because I have gone through several batteries, it's a 2000 for god's sake! I can't believe that changing the car battery would do that. So I searched this forum and found the reprogramming proceedger. Went through all the monkey motion, doors open, doors closed,key in ,key out, blah, blah, blah. Many times. Still no luck. What's my next move? There has to be something else wrong with either the fob itself, or the receiver inside the vehicle. Any ideas? Thanks.
Keyless entry problem
- Thread starter 4SKIN
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TheDurk
Elite Member
First thing to check is if there are any booboos in the wiring harness between the liftgate and the body of the car. Broken insulation or wires, etc. This is very common. The receiver is in the liftgate; the brains are part of the Body ECU by the driver's left knee.
Do all back-door functions work? Defrost, wiper, window (from dash switch), lock (using the key in the front) , window key switch in the hatch?
If no problem there, it gets more complicated. Do you have a digital multimeter (DMM)?
Do all back-door functions work? Defrost, wiper, window (from dash switch), lock (using the key in the front) , window key switch in the hatch?
If no problem there, it gets more complicated. Do you have a digital multimeter (DMM)?
Thanks for the response. Yes everything works as it should except the key fob. And the fob appears to be putting out a signal atleast at the autozone remote check display. I have a bearcat scanner and if I knew what frequency it used, I guess I could double check it against that. I have some electronics background and own several DMM and analog meters. One thing I don't have is a factory service manual. Considering it's age, I should probably invest in one. do you think a manual would address this problem?
TheDurk
Elite Member
Not really. First off, the FSM only addresses factory systems and prior to 1999, most were dealer and port add-ons. Really need to know your year and whether you have an alarm to know what system you have (there were several). On the factory '99-'02 system, the FSM just has this for troubleshooting:
It's a 2000 SR5. How would I know if it has an alarm? The fob does have a panic button on it. Of course that doesn't work either. I don't have any blinking lights on the dash to indicate that a security alarm would be armed when all the doors are locked. My key is not chipped. My owners manual has a section in it about an engine disabling device, but mine does not appear to have that function. I really appreciate all your help.
Thanks. I don't believe I have an alarm on this vehicle. No security warning light that I can see.
Well, after doing some extensive research, looks like I'm going to have to break down and buy a new fob. The conciseness is that these things only last about 10 years or less. I can't trust the autozone reader because evidently you have to be within 2" of it so it may indicate a signal, but it may be too weak to actually go any distance and through metal. I did find they operate at a freq. of 315MHZ, but my scanner will not cover those. It will do higher and lower, just not the 300MHZ range. Some privacy thing I believe. I even went as far as probing it with my oscilloscope after opening it up. There are some test points on the board, but I have no idea what their values are suppose to be,so my readings are of no help. When I get some extra dough (100 bucks) I'll spring for a new one and let everyone know what happened.
Ideas to troublshoot this?
Hi all. I'm reviving this old thread because I have this issue. 2000 4Runner SR5 4WD. Here are the symptoms:
- Key fob worked for years then suddenly was intermittent for a few days (would work sometimes, then not). Then after a week or two it stopped working altogether.
- Liftgate window doesn't power down or up (with key in tailgate or with dash button)
- Liftgate wiper doesn't work
Here's what I've tried
- replaced key fob battery (no help)
- rebent metal tabs that contact fob battery (no help)
- trying reprogramming the key fob with the key/locking5x/door sequence (no help)
I'm guessing the liftgate issues (wiper and window) are a sign of something going on in the control unit in there. Is that right? What would be the next step to address this - pop open the rear liftgate panel? What would I be looking for? Is this likely a control unit issue (can that be replaced?) or a wiring fault? Thanks for any ideas!!
Hi all. I'm reviving this old thread because I have this issue. 2000 4Runner SR5 4WD. Here are the symptoms:
- Key fob worked for years then suddenly was intermittent for a few days (would work sometimes, then not). Then after a week or two it stopped working altogether.
- Liftgate window doesn't power down or up (with key in tailgate or with dash button)
- Liftgate wiper doesn't work
Here's what I've tried
- replaced key fob battery (no help)
- rebent metal tabs that contact fob battery (no help)
- trying reprogramming the key fob with the key/locking5x/door sequence (no help)
I'm guessing the liftgate issues (wiper and window) are a sign of something going on in the control unit in there. Is that right? What would be the next step to address this - pop open the rear liftgate panel? What would I be looking for? Is this likely a control unit issue (can that be replaced?) or a wiring fault? Thanks for any ideas!!
Mark4runnar
Member
Brian.
Member
3rd, the "brain" for the fobs are in the rear hatch
You guys rock! Just started to watch the video referenced. Popped the rubber boot where the wires come through the rear liftgate and - whammo - couple broken wires staring me in the face. I'll repair those and expect that should sort it out. Thanks for the fast, on-point responses!
Good luck with the fix! When I did mine I took the whole rear harness off so I can solder new wires together but Tim's method is quick and just as effective!
Thanks again to Skulking, Bad Luck, and others here. As I mentioned, followed the video link and sure enough there were three broken wires in the bend going to the lift gate (link to pic below). I stripped those and soldered them back together. Window and door locking now working correctly. Thanks again!
Dropbox - 2021-11-15 11.40.51.jpg - Simplify your life
Dropbox - 2021-11-15 11.40.51.jpg - Simplify your life
Check the wiring loom for the rear hatch. Just because you think everything is working (clearly everything isn't working) doesn't mean that there aren't broken wires in there.