kwhiteside

I've got one key set and am trying to setup another.

I have ordered an extra FOB already and ready to order the key. To get the right one I have read that I need the ohms of my current key to get the right blank.

Can someone please explain to me how to get this reading from the key with a multi meter. Please give idiot proof instructions. Since I just came back from Radio Shack and tried every meter setting and touched every place possible on the key and never got any readings at all, I must fit into the idiot category. I'm not sure where to touch the key and do not know how to use the multi meter either. The Radio Shack person was no help.

I would guess that you touch the red and black leads to both sided of the little black computer chip in the key, and set the multi meter to the upside down horseshoe which I believe stands for ohms, but that did not give any readings at all.

Thanks in advance.

1998whitecoupe-a4

yup, put the volt meter on "ohms" - upside down horseshoe

take either prod - red or black, and place one on each side of the key chip only, read the ohms.

It's easier if you have someone hold the key though.

Just did mine, it was 953 or something, Vat #14.

rws.1

the "chip" is a black plastic insert in the shaft of the key next the head of the key.
Within the "chip" is a metal insert that is visible on both sides of the chip.
It is both sides of that insert that you need to touch the leads from the multi-meter.
1 lead on each side.

kwhiteside

Hmmm, that is exactly what I did.

Any chance you can give me the model of your multi meter? They had about 15 of them at Rad Shack. 8 reading, 12 reading all the way to 42 reading, bla, bla, bla, I'm not an electrician and it seems nobody at the Radio Shack electronics store is either! Perhaps if I try the same one. The one I tried had many many buttons. I could not get any reading though.

Carz4Toyz

You need to use any digital meter. be sure to touch only the little metal poins on the "chip", and as was posted earlier, turn the **** to the little upside down horseshoe. Good luck.

Stock Man

If you have a regular analog meter check to ensure you are on the right scale. If the scale is to high it won't register. Also zero the meter before you try and read the chip. Put both leads together and adjust the meter to read zero. Then one lead on either side of the chip and you should be able to read it.

VATS key codes
To read the resistance of the key with a digital volt meter, set it on ohms mode and measure the resistance of the pellet on your key.
The BCM is programmed for a specific resistance value. The BCM measures the voltage drop across the key pellet.
If it is within +/-10%, then the car will start.
The 15 resistor codes are:
Key# Value (Ohms)
1 - 392
2 - 523
3 - 681
4 - 887
5 - 1130
6 - 1470
7 - 1870
8 - 2370
9 - 3010
10 - 3740
11 - 4750
12 - 6040
13 - 7500
14 - 9530
15 - 11800

mschamberger

Unlike reading current you need to make sure you have batteries in the multi-meter when reading resistance. The multimeter itself needs to generate the current.

I'm not trying to insult you with this bit of info.

kwhiteside

I have managed to read the key on two different digital meters now. Both of them came up with 3.73. The only setting that would register is the -2000, all of the others give nothing.

I stopped at Pep Boys and they were nice enough to read it for me on two different meters. I showed them the paper stating the ohms should be in the 100's. We tried about every setting under the ohm part and could only get the 3.73.

What gives??

FM

The dealer can get you the correct key and cut it using your VIN.

RLYSLO

maybe you were measuring your differential gear ratio? j/k might be the 3740 one, but the dealer can tell you for sure as someone has mentioned.

kwhiteside

I found a Multi Meter in my Networking toolkit that only has one ohm setting. It reads 3.73k. I'm gonna intrepret that as 3730, which means I need the 3740 key.

I've heard the st-dealers want $246 for that key. It cost $15 on ebay once you know the right reading.

It is done!

Thanks for bearing with me.

Stock Man

Great, the reading is correct. The K means 1000 so 3 = 3000 and .73 = 730 so 3000 plus the 730 = 3,730 Ohms. If you don't do it every day it can be hard to get your head around it. But you got it. and I am glad you are not paying stealership prices. Maybe you should go back to them and let them know. Better yet call GM and let them know their dealers are ripping off the public maybe GM only charges $20 who knows!

DAVZ06

FYI I had mine made at a dealer here in Conn total cost was 30 bucks

Mike