Question: Another Key Fob Question

[twiget]

So riddle me this: I usually use key fob #1, and every time I go to open the door with the fob in my pocket, it opens, just like it is supposed to. Lately however, when I try to start the car, there will be a lot of clicking, and the DIC will show "No Fob Detected", and the security icon will turn on. If I push a button on the key fob (does not seem to matter which one), the security icon turns off and she starts right up, presumably because she recognizes the fob now.

This has happened a couple of times, so I thought it might mean a low battery. So I popped it into the recharge slot in the glove box for a little over an hour. After the fob had charged, I took the fob out of the charger and hit the start button. Again the DIC shows "No Fob Detected", so it looks like it is not the battery in the fob. After I pushed a button on the fob though, she started right up. Just for grins, I tried using the #2 fob for several days and I had no issues at all.

This coupled with lemish's C6 auto-dimming mirrors not working 1/2 the time thread, I'm starting to wonder if the issue is with the way the car recognizes the #1 fob, and not the fob itself. Any thoughts on what might be causing this issue?

Jason

 

[ScottNoxid]

So riddle me this: I usually use key fob #1, and every time I go to open the door with the fob in my pocket, it opens, just like it is supposed to. Lately however, when I try to start the car, there will be a lot of clicking, and the DIC will show "No Fob Detected", and the security icon will turn on. If I push a button on the key fob (does not seem to matter which one), the security icon turns off and she starts right up, presumably because she recognizes the fob now.

This has happened a couple of times, so I thought it might mean a low battery. So I popped it into the recharge slot in the glove box for a little over an hour. After the fob had charged, I took the fob out of the charger and hit the start button. Again the DIC shows "No Fob Detected", so it looks like it is not the battery in the fob. After I pushed a button on the fob though, she started right up. Just for grins, I tried using the #2 fob for several days and I had no issues at all.

This coupled with lemish's C6 auto-dimming mirrors not working 1/2 the time thread, I'm starting to wonder if the issue is with the way the car recognizes the #1 fob, and not the fob itself. Any thoughts on what might be causing this issue?

Jason

This sounds like a job for Lt4man, he is our expert on Key Fob's. In fact he just solved a big problem on them in Cleveland, and even got a prize for it. If I were you I would send out a FOB for the caped crusader, and all will be, well whatever slang they use. Good Luck;help

 

[SpryGeezer]

That's not a re-charge outlet in the glove box, it's an emergency receptacle for a fob with a dying fob battery, CR2032, cheap, which is not a re-chargeable battery.

 

[LT4man]

Hi, Jason!

c4c5specialist would be able to answer this question for you.

If he does not see your question, you can PM him.

Or you can go to http://corvettemechanic.com

That is his site and Chevy technicians & owners are always on it!

SAVE THE

 

[c4c5specialist]

HI there,
The first question is, do you have any aftermarket accessories in the vehicle that are electrically operated?
Second, when you put the fob in the slot in the glovebox and leave it in there, can you start the vehicle???
Allthebest, c4c5

 

[twiget]

The closest thing I've got to an electrically operated aftermarket accessory is the NPP bypass switch I installed. I did not experience this key fob issue until about a month after I installed the NPP switch, so I doubt the switch has anything to do with this.

As for starting the car with the fob in the glove box receptical, I tried that this morning. The first time I pressed the start button the DIC showed "No Fobs Detected". The second time I pressed the start button she started right up. I didnt wait very long between putting the fob in the receptical and pressing the start button though.

Jason

 

[c4c5specialist]

HI there,
Ok, what that pocket does is bounce an electrical signal OFF the fob, creating a signal that can be read and seen that you have the correct fob.
Now, attempt to start the car with the other fob, does it start right up or do you have to install the other fob into the pocket also?
Allthebest, c4c5

 

[NORTY]

Sounds like a weak FOB battery in #1.

 

[twiget]

HI there,
Ok, what that pocket does is bounce an electrical signal OFF the fob, creating a signal that can be read and seen that you have the correct fob.
Now, attempt to start the car with the other fob, does it start right up or do you have to install the other fob into the pocket also?
Allthebest, c4c5

She started right up with fob #2.

Jason

 

[danl72]

That's not a re-charge outlet in the glove box, it's an emergency receptacle for a fob with a dying fob battery, CR2032, cheap, which is not a re-chargeable battery.

I agree.

 

[twiget]

Sounds like a weak FOB battery in #1.

I do not think the battery is the issue. You saw my thread about the long range of the fob, and how the alarm was being triggered because the panic button was pressed while the fob was in my pants pocket. This is at a range of ~20 yards.

My understanding of the system is far from perfect, but the way I understand it is that when I press the start button, the car sends out an RF signal looking for a key fob. The fob will then respond with its own signal, and if the car recognizes the fob, she'll start.

If this is the case, why not use an RFID tag in the fob? It requires no power from the fob, and when the car sends out its RF signal looking for the fob, the RFID tag in the fob will bounce the same signal back (slightly tweaked by the tag), and if the returned signal matches what the car is expecting, she'll start.

This way, the only time the transmitter in the fob is used is when a button is pressed, which would increase the life of the battery.

Jason

 

[SpryGeezer]

........If this is the case, why not use an RFID tag in the fob? It requires no power from the fob, and when the car sends out its RF signal looking for the fob, the RFID tag in the fob will bounce the same signal back (slightly tweaked by the tag), and if the returned signal matches what the car is expecting, she'll start.
This way, the only time the transmitter in the fob is used is when a button is pressed, which would increase the life of the battery.
Jason

I assumed it works as you describe. Pushing a fob button energizes the fob to transmit using the fob battery, but pushing the engine start button or grabbing the door opener causes the car to poll the fob which then responds as a passive-retail-store-type RFID tag and reflects the car's query without using the fob battery for energy.
I wonder how it works.

 

[NORTY]

I do not think the battery is the issue. You saw my thread about the long range of the fob, and how the alarm was being triggered because the panic button was pressed while the fob was in my pants pocket. This is at a range of ~20 yards.

My understanding of the system is far from perfect, but the way I understand it is that when I press the start button, the car sends out an RF signal looking for a key fob. The fob will then respond with its own signal, and if the car recognizes the fob, she'll start.

If this is the case, why not use an RFID tag in the fob? It requires no power from the fob, and when the car sends out its RF signal looking for the fob, the RFID tag in the fob will bounce the same signal back (slightly tweaked by the tag), and if the returned signal matches what the car is expecting, she'll start.

This way, the only time the transmitter in the fob is used is when a button is pressed, which would increase the life of the battery.

Jason

You're right, I forgot about the 20 yard panic test you described earlier. Ok, so battery issue is out. Let's talk RF signals now. There is something that FOB #1 is or isn't doing correctly that differs from FOB #2. I was about to hypothesize that there was RF interference (ie:garage door opener, cellular phone, pager, alarm system, radar detector) but FOB 2 is having no problems. There must be a difference in FOB #1 that is the issue here. Has it been dropped, run through the washing machine (don't laugh!) or subjected to heat?

 

[jbeidl]

Do you know the build date for your car?

There was a problem with the early 2008's. If I recall correctly the Remote Entry electronics package had to be replaced because of "No FOB Detected" issues. Shipments were stopped for about 2 weeks until all of the inventory at the Bowling Green plant could be updated. Earlier shipments were supposed to have been corrected at the dealer.

If you search all of the different Corvette Forum archives (around July & August of 2007) you can probably find more details.

If you have an early build, it might still have the problem Remote Entry electronics.

Save The Wave,
John

 

[twiget]

I do not know the build date of my car, and short of buying a build sheet from the NCM I don't have any ideas on how to find out. Anyone know another way to find out the build date?

Jason

 

[jbeidl]

There should be a silver background tag on the rear edge of the drivers door frame (just below the door latch - at least that is where it is on an 07). The build month and year should be near the top left. Mine indicates 0806 and it was built on 8/30/2006 - I was there to watch it be assembled.

Save The Wave,
John

 

[twiget]

Spiffy. The date is 01/08. That would put her squarely in the middle of the build cycle.

Jason

 

[jbeidl]

Yes, that was long after the problem was found.

I don't know what the problem was but I know that they had to replace the Remote Control Door Lock Receiver which is located in the dash just above the radio. If I recall correctly the symptoms were "FOB not Detected" when the start button was pressed.

Save The Wave,
John

 

[Blue260]

Question answered - removed duplicate answer

 

[c4c5specialist]

Back to basics

HI there,
There are a few keys here.
First, if the car started right up with Fob #2 inside the vehicle but NOT in the pocket, you have just confirmed that the fob itself isnt working properly.
Replace the fob, and that should resolve your issue.
As for the reprogram of the RCDLR(remote control door lock receiver), this should have been the FIRST course of action by your dealership.
2005-2008 this revised calibration worked with all of them.
EMI/RFI are all common issues with these type systems.
As long as there is no aftermarket electrical accessories in the vehicle and your not parked near an electrical transformer, you should be just fine.
Allthebest, c4c5