Where to begin?

2005, lost key fob #1 with the trunk key, and key fob #2 (after being inactive for quite some time) is wonky.

I replaced the fob battery. Fob #2 will lock/unlock car and pop the trunk, but when I get in and attempt to start, I receive everyone’s favorite “Fob not found” message.

Placing fob #2 in the glove box column will allow the car to start.

Is this a dealership trip?

EDIT: Update 1

Since I’m a new member, my reply is awaiting moderation, so I’ll add some updates here (which will likely duplicate stuff in my post when it gets approved):

- Had new trunk keys cut.
- Purchased new batteries (again) and new fob.
- Entered long fob learning mode; after completing, neither fob would start the car—even when placed in the glove box slot.
- Both fobs (new and original) would lock/unlock/open trunk/activate alarm.
- Called dealership for flatbed pickup on Monday, since vehicle is stranded.
- Disconnected battery, and then opened fuse box under hood and removed/reseated fuses (I’m in IT, so this is a pretty common troubleshooting step to me)
- Reconnected battery.

Both fobs now work when placed inside the glove box slot, though now my airbag light is on and won’t go off. Grr.

Keeping my appointment for Monday, 8/24/2020.

 

 

My 05 6 Speed acted like this when the battery was old and needed replaced. Also kept hearing a clicking underneath hvac controls. I replaced fob battery(s) along with main battery and solved my problem.

 

Also, make sure your cell phone isn't right next to your fob, cell phones can cause interference with the fobs signal.

 

Just because you replaced the fob battery doesn't guarantee that the battery is fresh. This has been observed and commented on numerous times. Go to a retailer that sells lots of batteries like for example Wallyworld and try those. Name brand are best. Check also the expiration date on the package before you purchase.

 

The antenna in the glove box slot is the one that's used by the car when you push the start button. The slot also induces a voltage (magnetically) into the fob in case the battery is dead.

Try another fob battery and maybe move the fob closer to the glove box.

The fob's signal when responding passively to the car is much weaker than when you actively press any of the fob buttons.

 

Went to the dealer and had two new trunk keys cut from VIN for a grand total of $46.19.

Replaced batteries in both fobs (original and a brand new one) AGAIN with fresh batteries from the CVS on the corner.

Went through the long learn procedure. At the end of this process, NEITHER fob would start the car, even when in the glove box slot. 🤦🏼‍♂️

If I did the short learn procedure, it would say “Known fob.” Both fobs lock/unlock/open trunk/alarm, but neither would start the car.

Called the dealership for a flatbed referral and an appointment for Monday.

As a hail-Mary, I disconnected the battery. While disconnected, unplugged and reseated fuses under the hood to make sure they hadn’t somehow worked their way loose. Reconnected battery after 5 mins.

Both fobs now *start* the car, but only when in the slot. As a bonus, airbag light is now on, even though nothing else was done (not even moving the seat).

Keeping my dealership appointment tomorrow.

 

A few more points:
Lots of posts about weak car battery causing electronic problems. Check the battery voltage before you start the car. Fully charged you should see 12.6. Since you can at least start the car you should get the battery load tested.

If you want to check fuses, there are more in the passenger footwell.

Cell phones in close proximity to the fob have been known to cause problems. See if removing your cellphone from the car helps when you try to start it.

Devices plugged into the cigarette lighter ports have also caused interference problems, so remove any of those.

Strong EMI sources also interfere with fob communication.

If you are trying the disconnect the battery trick, while the cables are off, touch the ends together to fully discharge everything. This has been reported to work for some if us.

 

Dropped the car off at the dealership today. After being on for 2 days, airbag light is suddenly off. Typical car behavior--errors and codes, except when it feels threatened because you take it to a dealership. He did indicate that sometimes disconnecting the battery can cause the airbag light to come on briefly, but the computer should clear it. He said there was previously a TSB for cell phone and other RF interference when the phone was on the passenger seat causing the airbag light to come on as well. He experiences the issue with his Escalade and his HHR, he commented, and it's just a "feature" that has been fixed in later versions of the radio hardware. Never experienced the issue until last week, and I've had the same phone for about 2 years.

I explained the key fob/starting issue to the service adviser, and we verified the problem in the shop. "That's interesting" was the response. I've got nothing plugged into the car as far as power adapters/chargers and leaving my cell phone in the house still results in the same issue. Based on some things I've seen (and my experience with my 2010 STS), it seems like it may be the RCDLR antenna?

He scanned the computer's codes while I was watching, and my airbag is not throwing a code anymore.

Getting one last look at my checking account before it vanishes. ;-)

 

As to the RCDLR antenna, that would be unlikely (not impossible I guess) because you were able to perform the long procedure. The antenna that the fobs communicate with in order to start the car and do the programming would be the one right behind the glove box slot, so if it was inop, then how are you able to start the car with the fob in the slot, and how were you able to program fobs?

I had an airbag light problem intermittently for 2 years, progressively worse. The cure for that in my case (and many others) was to undo the big yellow connector under the driver's seat, making sure the contacts are clean, and reassembly with some dielectric grease. If the light returns, and if you were going to do this, you probably should disconnect the battery to prevent accidental deployment of the air bag. The whole thing takes maybe 15 minutes, and is very easy. If it is the connector, the problem in letting the dealer fix it is that they sometimes deal with it by cutting the connector out, and soldering the wires back together. Good luck removing the driver's seat if they do that.

 

Got the call back from the dealer.

The RCDLR unit itself is bad. So, $640 installed.

Better safe than stranded.

 

Indeed, it was the RCDLR. Got the car back and both fobs are working as designed and the car starts normally with the fob in my pocket.

 

Glad you got that sorted out and it didn't turn into a giant PITA.