replace Key Fob Battery?

htmlspinnr · 09-03-2006, 12:10 PM

I'm at 65k miles and nearly 3 years (in Oct), and still on my original batteries (and my car has SKS). I think I've rotated through the FOBs though at some point which may help.

The FOB will continue to start the car as it's passive RFID when insterted into the dash. If the battery dies, you simply need to use the manual key.

Frank Hudon · 09-03-2006, 12:20 PM

I've done the fobs for both cars and just recently I've found that the 2k4 arming distance has dropped by half again. So I'm going to pull the battery and measure the voltage and see if its down, which I suspect it will be, and I'll probably change it again. By arming distance, about 120 feet with new and last weekend I had trouble setting at about 45'.
Edit: checked and it's now at 3.013 volts. it was at 3.13 when new. I guess I'll change it.

tumbleweed · 09-03-2006, 04:02 PM

Wow! live and learn. I always thought prophylactic was just a fancy name for a rubber. Thank you so much.

sand0 · 01-28-2007, 06:11 AM

I have a BIG problem.
I changed the battery but the fob can't synchronize with the car (2004 prius).
The fob light flashes the car flashes but at the end the fob can't unlock the car.

What I'm missing here??

sand0 · 02-04-2007, 06:18 PM

<div class='quotetop'>QUOTE(sand0 @ Jan 28 2007, 06:11 AM) [snapback]381895[/snapback]</div>

Quote:

I have a BIG problem.
I changed the battery but the fob can't synchronize with the car (2004 prius).
The fob light flashes the car flashes but at the end the fob can't unlock the car.

What I'm missing here??
[/b]

ANY ONE?

Bill Merchant · 02-05-2007, 01:42 AM

If you stick the fob in the dash slot, can you power-on the car?

sand0 · 02-05-2007, 03:12 PM

<div class='quotetop'>QUOTE(Bill Merchant @ Feb 5 2007, 01:42 AM) [snapback]385434[/snapback]</div>

Quote:

If you stick the fob in the dash slot, can you power-on the car?
[/b]

Yes the car power and run.
but the fob light don't come and I can't unlock/lock the car with the remote anymore

sand0 · 02-06-2007, 05:15 PM

<div class='quotetop'>QUOTE(sand0 @ Feb 5 2007, 03:12 PM) [snapback]385665[/snapback]</div>

Quote:

Yes the car power and run.
but the fob light don't come and I can't unlock/lock the car with the remote anymore

[/b]

My English is not so good. I'm talking for the remote control. And I'm not sure the fob and remote is the same.
So we are talking about the remote control red light not coming when the open/close button is pressed nor the car unlock/lock.

The red led light only when I replace the battery and the remote try to conect with the car (the car is flashing some lights too

)

Bill Merchant · 02-07-2007, 01:02 AM

Well, the good news is you can still start and drive your car. The bad news is you can't lock/unlock it using the fob. I think the fob and the remote, as you've called it, is the same device, right? A little plastic box with a removable metal key (slide a latch at the bottom), a red panic button above that, then the unlock button, and the lock button at the top? There's a tiny LED under the surface on the right side of the lock button, right?

If the little LED flashes for a split second when you push the lock button, your car should lock. If there's enough power to flash the LED, there should be enough power to send a signal to the car, particularly if you are standing close.

You didn't say whether you have an Smart Key System or not. With the SKS, there is a little rubber square on the door handle; pushing it will lock the doors, putting your hand in the handle to open the door will unlock it, so you don't have to use the fob buttons.

I think I'd try replacing the fob battery again. That's a pretty inexpensive battery, and it could be that the new battery you used was old and low powered.

If that doesn't work, it's time to visit the dealer, unfortunately. The dealer's scan tools are needed to solve fob problems.

Good luck!

sand0 · 02-07-2007, 06:54 PM

yep the plastick box

No it is not the smart entry.

I found somewhere in the service manuals how to reprogram the key. But I lost it

it was wile ago.
I have to find it again.

09-03-2006, 12:20 PM	#12
Frank Hudon Senior Member Join Date: Jan 2004 Posts: 4,144 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I've done the fobs for both cars and just recently I've found that the 2k4 arming distance has dropped by half again. So I'm going to pull the battery and measure the voltage and see if its down, which I suspect it will be, and I'll probably change it again. By arming distance, about 120 feet with new and last weekend I had trouble setting at about 45'. Edit: checked and it's now at 3.013 volts. it was at 3.13 when new. I guess I'll change it. __________________ You can quote me on this, People who drive vehicles that idle at a traffic light, are idiots. mine 2k3 avg. 5.36 for 46,915Km Best tank 4.4L per 100K 64.2 Imperial 53.4 U.S. gallon, MiniScanner, SilverStars, block heater, winter lips, in as of Oct 15, out on April 25. In again on Sept. 21st. her's 2k4 "B" avg. 6.01 for 42,317 Km Best tank 4.02L per 100K, CAN-view with OBD11 module and flashloader, SilverStars, 06 Chrome grill bar, Michelin HydroEdge, upper and lower grill blocker,upper out as of April 7, lower out on April 28. In again on Sept 21st.

02-07-2007, 01:02 AM	#19
Bill Merchant absit invidia Join Date: May 2005 Location: USA \| Oregon \| Portland area \| 97004 \| Posts: 3,964 My Car: 2007 Prius Package: #5 Nominated 6 Times in 1 Post TOTM Awards: 1 Friends: 53	Well, the good news is you can still start and drive your car. The bad news is you can't lock/unlock it using the fob. I think the fob and the remote, as you've called it, is the same device, right? A little plastic box with a removable metal key (slide a latch at the bottom), a red panic button above that, then the unlock button, and the lock button at the top? There's a tiny LED under the surface on the right side of the lock button, right? If the little LED flashes for a split second when you push the lock button, your car should lock. If there's enough power to flash the LED, there should be enough power to send a signal to the car, particularly if you are standing close. You didn't say whether you have an Smart Key System or not. With the SKS, there is a little rubber square on the door handle; pushing it will lock the doors, putting your hand in the handle to open the door will unlock it, so you don't have to use the fob buttons. I think I'd try replacing the fob battery again. That's a pretty inexpensive battery, and it could be that the new battery you used was old and low powered. If that doesn't work, it's time to visit the dealer, unfortunately. The dealer's scan tools are needed to solve fob problems. Good luck! __________________ Bill Bill.Merchant@PortlandHSD.info 2007 NL 5 Silver Wraith 2005 BC 6 Silver Cloud Portland Area HSD Meetup Group: PortlandHSD.info Become carbon neutral: Carbonfund.org or TerraPass.com

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Replace Battery in key warning	Samsurfer	Care, Maintenance and Troubleshooting	22	12-26-2007 07:27 PM
$7,000 to replace the battery?!	Spoon	Prius Technical Discussion	9	08-06-2007 09:48 PM
Replace 12v battery?	lagreca	Prius Main Forum	14	07-30-2007 03:52 PM
2001 Prius battery problem...replace cells?	lutung	Prius Technical Discussion	4	07-29-2007 12:26 PM

09-03-2006, 12:10 PM	#11
htmlspinnr Senior Member Join Date: Dec 2003 Location: Surprise, AZ (Phoenix) Posts: 1,304 My Car: 2004 Prius Package: Pioneer #3 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 1	I'm at 65k miles and nearly 3 years (in Oct), and still on my original batteries (and my car has SKS). I think I've rotated through the FOBs though at some point which may help. The FOB will continue to start the car as it's passive RFID when insterted into the dash. If the battery dies, you simply need to use the manual key.

09-03-2006, 04:02 PM	#13
tumbleweed Senior Member Join Date: Oct 2005 Location: Eastern Oregon Posts: 1,006 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Wow! live and learn. I always thought prophylactic was just a fancy name for a rubber. Thank you so much.

01-28-2007, 06:11 AM	#14
sand0 Join Date: Dec 2005 Posts: 12 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I have a BIG problem. I changed the battery but the fob can't synchronize with the car (2004 prius). The fob light flashes the car flashes but at the end the fob can't unlock the car. What I'm missing here??

02-05-2007, 01:42 AM	#16
Bill Merchant absit invidia Join Date: May 2005 Location: USA \| Oregon \| Portland area \| 97004 \| Posts: 3,964 My Car: 2007 Prius Package: #5 Nominated 6 Times in 1 Post TOTM Awards: 1 Friends: 53	If you stick the fob in the dash slot, can you power-on the car?

02-07-2007, 06:54 PM	#20
sand0 Join Date: Dec 2005 Posts: 12 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	yep the plastick box No it is not the smart entry. I found somewhere in the service manuals how to reprogram the key. But I lost it it was wile ago. I have to find it again.