2008 key fob will not open doors or hatch intermittently
11-26-2021, 08:37 AM
#1
Cruising
Thread Starter
2008 key fob will not open doors or hatch intermittently
I have seen many threads on issues with key fobs not working, door not opening, etc. I just haven't found one that matches my symptoms. Usually after sitting over night, I can't get in the car with the fob. Neither using the buttons nor my fingers on the door/hatch switches will open them. It take multiple tries over several minutes before finally one of the methods decides to work. Once I am able to get in the car it has no problem starting and does not give the fob not recognized message. I have replaced the key fob battery and the car battery. The car battery's age was unknown as we have had the car for 3 years so replaced it with Interstate battery. After doing that everything seemed to be working. Had not driven the car in a day or two and this morning it is happening again. I can't use the physical key in the hatch because we have a backup camera license plate and it is in the way. So since I know I have a new car battery and new key fob battery (voltage verified), do I have a flaky RCDLR? If so, is that something a car novice can replace or do I need a mechanic?
My other key fob also has the problem but after replacing the battery in it, it doesn't work at all now. I will work on that problem later as the other fob does still function (with the above issues of course).
My other key fob also has the problem but after replacing the battery in it, it doesn't work at all now. I will work on that problem later as the other fob does still function (with the above issues of course).
11-26-2021, 10:01 AM
#2
Team Owner
When replacing your fob batteries, be sure that you buy them from some place that sells lots of batteries, like WalMart. Also don't have anything plugged into the electrical outlet in the car's console.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
The following 2 users liked this post by Vette_DD:
GriMacE912 (11-27-2021),
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11-26-2021, 10:35 AM
#3
Drifting
Here are a couple of things I would do. I know you have a new battery, but you didn't mention if you thoroughly cleaned the battery terminals when you installed that new battery, so I would clean the battery terminals with a tool intended for that purpose (buy one if you don't have one). Then, I would also connect a battery maintainer to your car. After doing those things, see if the problem goes away.
11-26-2021, 10:51 AM
#4
Cruising
Thread Starter
When replacing your fob batteries, be sure that you buy them from some place that sells lots of batteries, like WalMart. Also don't have anything plugged into the electrical outlet in the car's console.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
11-26-2021, 11:12 AM
#5
Cruising
Thread Starter
When replacing your fob batteries, be sure that you buy them from some place that sells lots of batteries, like WalMart. Also don't have anything plugged into the electrical outlet in the car's console.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
The fob battery is Energizer and I verified the voltage was 3.2v. The Interstate battery was just replaced Wed 11/24 and my wife was able to get in the car several times that day. Didn't drive it on Thanksgiving and this morning can't get in. After 5-10 of trying it suddenly started working. Now I just went out in the garage (same place it has been parked for the 3 yrs we have owned it), the fob is not working/being recognized again. I was planning to check voltage of the new car battery but can't get in. I used the manual key (after removing backup camera license plate frame) and alarm started going off. I did the manual release for the drivers door and it did pop open but I still couldn't fully open it (assuming this is a different problem that needs to be resolved). So bottom line, I can't get in the car at all right now. Keep in mind that when the fob doesn't work/not sensed, None of the doors will open (driver/passenger/hatch). Once it does decide to work, the car always starts and we don't get any "fob not detected" message.
11-26-2021, 11:35 AM
#6
Safety Car
Member Since: Aug 2017
Location: Etobicoke (Toronto) Ontario
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First - a comment: I'd say you need to have an alternate strategy for your backup camera, one that allows you to use the key to pop the hatch. What are you going to do if you are on the road, and the car battery dies, or the fobs stop working? And with quality as it is these days, even your new battery may not last that long.
As far as the second fob is concerned, did you insert the new battery the correct way up? You wouldn't be the first to put it in upside down.
I'd also say you should keep your battery hooked up to a maintainer, particularly if you take short drives. You might not be driving it enough for the alternator to replace the charge lost from starting the car. That voltage seems a bit low to me. Fully charged, should be something like 12.6 volts. Before doing anything else, I'd verify that the new battery is fully charged and can pass a load test, and that alternator output is correct.
If the battery and charging system check out correctly, read the attached TSB. There is a known problem that can occur with the RCDLR, and the TSB will tell you how to troubleshoot it. I'm not sure if the transistor on the RCDLR circuit board that causes this TSB problem can be replaced. The TSB just says to replace the RCDLR, but that's typical of GM, who seem to be reluctant to try to repair anything. You can replace the RCDLR yourself, if you can find one, and it's not that difficult a job. However, you will need a Tech2 tool to marry the new RCDLR to the system, and may (I can't remember) need to reprogram the fobs and TPMS sensors.
Lastly, as the RCDLRs age, there is a possibility that the solder joints for the relays and antennas become disconnected or otherwise weakened to the point of poor connection. This has been reported before, and it is possible to remove the RCDLR and repair the solder joints if you know what you are doing.
As far as the second fob is concerned, did you insert the new battery the correct way up? You wouldn't be the first to put it in upside down.
I'd also say you should keep your battery hooked up to a maintainer, particularly if you take short drives. You might not be driving it enough for the alternator to replace the charge lost from starting the car. That voltage seems a bit low to me. Fully charged, should be something like 12.6 volts. Before doing anything else, I'd verify that the new battery is fully charged and can pass a load test, and that alternator output is correct.
If the battery and charging system check out correctly, read the attached TSB. There is a known problem that can occur with the RCDLR, and the TSB will tell you how to troubleshoot it. I'm not sure if the transistor on the RCDLR circuit board that causes this TSB problem can be replaced. The TSB just says to replace the RCDLR, but that's typical of GM, who seem to be reluctant to try to repair anything. You can replace the RCDLR yourself, if you can find one, and it's not that difficult a job. However, you will need a Tech2 tool to marry the new RCDLR to the system, and may (I can't remember) need to reprogram the fobs and TPMS sensors.
Lastly, as the RCDLRs age, there is a possibility that the solder joints for the relays and antennas become disconnected or otherwise weakened to the point of poor connection. This has been reported before, and it is possible to remove the RCDLR and repair the solder joints if you know what you are doing.
11-26-2021, 11:53 AM
#7
Seen so many times on this forum that issues start with the car battery. Your battery may be new but as others have said make sure the cable at the battery connections is perfectly clean. Also make sure the connections are very snug. Especially the negative post connection which is often problematic. The connections are "conical" and may sometimes seem tight when they're not. Try to wiggle them to check. Invest in a battery maintainer such as Battery Tender and always keep it connected and powered when parked. Good luck.
11-26-2021, 01:22 PM
#8
Cruising
Thread Starter
Seen so many times on this forum that issues start with the car battery. Your battery may be new but as others have said make sure the cable at the battery connections is perfectly clean. Also make sure the connections are very snug. Especially the negative post connection which is often problematic. The connections are "conical" and may sometimes seem tight when they're not. Try to wiggle them to check. Invest in a battery maintainer such as Battery Tender and always keep it connected and powered when parked. Good luck.
As for a battery maintainer - this car is a daily driver for my wife so I think connecting and disconnecting a maintainer is not realistic here.
11-26-2021, 01:34 PM
#9
Cruising
Thread Starter
When replacing your fob batteries, be sure that you buy them from some place that sells lots of batteries, like WalMart. Also don't have anything plugged into the electrical outlet in the car's console.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
Where is your car being parked overnight? Not near any external electric force field is it?
Check the car battery's voltage.
11-26-2021, 03:56 PM
#10
Safety Car
Member Since: Aug 2017
Location: Etobicoke (Toronto) Ontario
Posts: 4,021
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Connecting and disconnecting the maintainer is as simple as plugging and unplugging the adapter into the cig lighter receptacle in either the dash or in the console. And just because it's driven daily doesn't guarantee the battery is kept charged. The OEM alternator doesn't put put enough amps at idle RPM to keep up with the draw from the rad fan. The car needs to be driven long enough and fast enough to replace the energy lost from starting it. 15 minutes should be long enough, but not 15 minutes stuck in traffic with rad fan, lights, HVAC fan running. Rear defrost and seat heater to make it much worse.
11-26-2021, 04:02 PM
#11
Connecting and disconnecting the maintainer is as simple as plugging and unplugging the adapter into the cig lighter receptacle in either the dash or in the console. And just because it's driven daily doesn't guarantee the battery is kept charged. The OEM alternator doesn't put put enough amps at idle RPM to keep up with the draw from the rad fan. The car needs to be driven long enough and fast enough to replace the energy lost from starting it. 15 minutes should be long enough, but not 15 minutes stuck in traffic with rad fan, lights, HVAC fan running. Rear defrost and seat heater to make it much worse.
11-26-2021, 04:30 PM
#12
Safety Car
Member Since: Aug 2017
Location: Etobicoke (Toronto) Ontario
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Where did you get that info from? I used to do major car audio work back in the day and was common knowledge that 'revving' the engine to get more power from your alt was unnecessary as max draw was always present even at idle via voltage regular. If revving your car higher = more power then people would be blowing electronics left and right.
11-26-2021, 04:45 PM
#13
Team Owner
Vette_DD - where do you take your Vette for service? I noticed you are in southern middle TN and I am just east of Nashville. In the 3 yrs I have owned it, I have not had to take it to a mechanic. Looking for a reliable mechanic that knows Corvettes. Dealership pricing is ridiculous as we all know.
11-26-2021, 05:23 PM
#14
12.2V on the battery (should be charged up to around 13.4 when the car is shut off), is a lot of battery voltage drop off in a few days when the modules are suposed to be in sleep mode. So on this one, would do a parasitic draw test on the car to figure out what is draining the battery that quick/what module is not going to sleep.
Note, if the car has either XM, or ONStar and you are not using them with subscprition, disconnect the fuses for both. Hence even without a subscription, both will trying to call home in off hours, and will not stop trying until they can connect.
As for fob working once you do get into the car with the RCDLR working to start the car, battery disconnect, 10 min wait, then reconnecting the battery will reset all the modules once you have solved the parasitic draw problem. Just remember that you will need to reindex the windows once the battery is reconnected.
As for RCDLR, could be its connector, Hence The BCM connectors, Engine fuse block lower to upper box connectors, the engine fuse box main terminal connector or could be the splice block connectors for both the RCDLR power and grounds that are corrode to cause the low voltage problems over just the lower voltage battery drain problem. Hence once the RCDLR does come to life with enough power to allow you to get into the car, it's also allowing the car to start since that requires that two of the Fob antenna's picks up the Fob to show its in the car cabin. Simply, power to modules in the car starts from battery, to engine fuse box terminal, through the fuse box to the BCM, then out of the BCM to the modules. So In the case of the RCDLR, it has a total of 3 spice blocks that links it back to the BCM. Once spice block for the power that leads back to the BCM, another for the ground that has a wire coming out of that block to ground of the chassic, then a third spice block just left of the Bose amp location that connects it to the BCM data 2 bus for comunication to the BCM.
So again, since the Fob is allowing you to start the car in the end, it really not the RCDLR the problem, but a corrosion problem on one of the wires or connector pins the problem; with the lower voltage out of the battery after a few days not helping the problem either.
Welcome to electrical gremlins that some times can be a Bitch to solve if you don't know How and Where to look for them. And no, would keep this one away from the dealers, since they will just throw parts at the car, until they do stumble onto the corrosion problem to solve it in the end. So if you are unable to work on the car yourself, go find a good Indy shop that is very good about electrical trouble shootings the C6's.
If you are in the Denver area, can give you a hand over at my house to solve the problem in a few hours most, since it mostly a labor kind of thing, and just need to bring a can of CRC electrical spray cleaner, hence its the Parts part of the math to clean the connectors/wires as you go through the electrical connector parts of the system, and seeing what is after market that may not have been wired correctly to begin with.
Note, if the car has either XM, or ONStar and you are not using them with subscprition, disconnect the fuses for both. Hence even without a subscription, both will trying to call home in off hours, and will not stop trying until they can connect.
As for fob working once you do get into the car with the RCDLR working to start the car, battery disconnect, 10 min wait, then reconnecting the battery will reset all the modules once you have solved the parasitic draw problem. Just remember that you will need to reindex the windows once the battery is reconnected.
As for RCDLR, could be its connector, Hence The BCM connectors, Engine fuse block lower to upper box connectors, the engine fuse box main terminal connector or could be the splice block connectors for both the RCDLR power and grounds that are corrode to cause the low voltage problems over just the lower voltage battery drain problem. Hence once the RCDLR does come to life with enough power to allow you to get into the car, it's also allowing the car to start since that requires that two of the Fob antenna's picks up the Fob to show its in the car cabin. Simply, power to modules in the car starts from battery, to engine fuse box terminal, through the fuse box to the BCM, then out of the BCM to the modules. So In the case of the RCDLR, it has a total of 3 spice blocks that links it back to the BCM. Once spice block for the power that leads back to the BCM, another for the ground that has a wire coming out of that block to ground of the chassic, then a third spice block just left of the Bose amp location that connects it to the BCM data 2 bus for comunication to the BCM.
So again, since the Fob is allowing you to start the car in the end, it really not the RCDLR the problem, but a corrosion problem on one of the wires or connector pins the problem; with the lower voltage out of the battery after a few days not helping the problem either.
Welcome to electrical gremlins that some times can be a Bitch to solve if you don't know How and Where to look for them. And no, would keep this one away from the dealers, since they will just throw parts at the car, until they do stumble onto the corrosion problem to solve it in the end. So if you are unable to work on the car yourself, go find a good Indy shop that is very good about electrical trouble shootings the C6's.
If you are in the Denver area, can give you a hand over at my house to solve the problem in a few hours most, since it mostly a labor kind of thing, and just need to bring a can of CRC electrical spray cleaner, hence its the Parts part of the math to clean the connectors/wires as you go through the electrical connector parts of the system, and seeing what is after market that may not have been wired correctly to begin with.
Last edited by Dano523; 11-26-2021 at 05:28 PM.
The following users liked this post:
GriMacE912 (11-27-2021)
11-26-2021, 06:17 PM
#15
Cruising
Thread Starter
12.2V on the battery (should be charged up to around 13.4 when the car is shut off), is a lot of battery voltage drop off in a few days when the modules are suposed to be in sleep mode. So on this one, would do a parasitic draw test on the car to figure out what is draining the battery that quick/what module is not going to sleep.
Note, if the car has either XM, or ONStar and you are not using them with subscprition, disconnect the fuses for both. Hence even without a subscription, both will trying to call home in off hours, and will not stop trying until they can connect.
As for fob working once you do get into the car with the RCDLR working to start the car, battery disconnect, 10 min wait, then reconnecting the battery will reset all the modules once you have solved the parasitic draw problem. Just remember that you will need to reindex the windows once the battery is reconnected.
As for RCDLR, could be its connector, Hence The BCM connectors, Engine fuse block lower to upper box connectors, the engine fuse box main terminal connector or could be the splice block connectors for both the RCDLR power and grounds that are corrode to cause the low voltage problems over just the lower voltage battery drain problem. Hence once the RCDLR does come to life with enough power to allow you to get into the car, it's also allowing the car to start since that requires that two of the Fob antenna's picks up the Fob to show its in the car cabin. Simply, power to modules in the car starts from battery, to engine fuse box terminal, through the fuse box to the BCM, then out of the BCM to the modules. So In the case of the RCDLR, it has a total of 3 spice blocks that links it back to the BCM. Once spice block for the power that leads back to the BCM, another for the ground that has a wire coming out of that block to ground of the chassic, then a third spice block just left of the Bose amp location that connects it to the BCM data 2 bus for comunication to the BCM.
So again, since the Fob is allowing you to start the car in the end, it really not the RCDLR the problem, but a corrosion problem on one of the wires or connector pins the problem; with the lower voltage out of the battery after a few days not helping the problem either.
Welcome to electrical gremlins that some times can be a Bitch to solve if you don't know How and Where to look for them. And no, would keep this one away from the dealers, since they will just throw parts at the car, until they do stumble onto the corrosion problem to solve it in the end. So if you are unable to work on the car yourself, go find a good Indy shop that is very good about electrical trouble shootings the C6's.
If you are in the Denver area, can give you a hand over at my house to solve the problem in a few hours most, since it mostly a labor kind of thing, and just need to bring a can of CRC electrical spray cleaner, hence its the Parts part of the math to clean the connectors/wires as you go through the electrical connector parts of the system, and seeing what is after market that may not have been wired correctly to begin with.
Note, if the car has either XM, or ONStar and you are not using them with subscprition, disconnect the fuses for both. Hence even without a subscription, both will trying to call home in off hours, and will not stop trying until they can connect.
As for fob working once you do get into the car with the RCDLR working to start the car, battery disconnect, 10 min wait, then reconnecting the battery will reset all the modules once you have solved the parasitic draw problem. Just remember that you will need to reindex the windows once the battery is reconnected.
As for RCDLR, could be its connector, Hence The BCM connectors, Engine fuse block lower to upper box connectors, the engine fuse box main terminal connector or could be the splice block connectors for both the RCDLR power and grounds that are corrode to cause the low voltage problems over just the lower voltage battery drain problem. Hence once the RCDLR does come to life with enough power to allow you to get into the car, it's also allowing the car to start since that requires that two of the Fob antenna's picks up the Fob to show its in the car cabin. Simply, power to modules in the car starts from battery, to engine fuse box terminal, through the fuse box to the BCM, then out of the BCM to the modules. So In the case of the RCDLR, it has a total of 3 spice blocks that links it back to the BCM. Once spice block for the power that leads back to the BCM, another for the ground that has a wire coming out of that block to ground of the chassic, then a third spice block just left of the Bose amp location that connects it to the BCM data 2 bus for comunication to the BCM.
So again, since the Fob is allowing you to start the car in the end, it really not the RCDLR the problem, but a corrosion problem on one of the wires or connector pins the problem; with the lower voltage out of the battery after a few days not helping the problem either.
Welcome to electrical gremlins that some times can be a Bitch to solve if you don't know How and Where to look for them. And no, would keep this one away from the dealers, since they will just throw parts at the car, until they do stumble onto the corrosion problem to solve it in the end. So if you are unable to work on the car yourself, go find a good Indy shop that is very good about electrical trouble shootings the C6's.
If you are in the Denver area, can give you a hand over at my house to solve the problem in a few hours most, since it mostly a labor kind of thing, and just need to bring a can of CRC electrical spray cleaner, hence its the Parts part of the math to clean the connectors/wires as you go through the electrical connector parts of the system, and seeing what is after market that may not have been wired correctly to begin with.
We have owned the car for 3 yrs (first Vette) and it came with after-market HU, Borla exhaust and window tint but otherwise is a stock base C6. It does have Onstar and we don't have the subscription so I will see about removing the fuse for that. Any details about doing the parasitic draw test would be appreciated.
11-27-2021, 11:09 AM
#16
Cruising
Thread Starter
Thank you so much for the very detailed explanation. That is very helpful. I am certainly not qualified to do a tear down to trace those out but I mostly understand what you are describing and I am not familiar with a parasitic draw test so not sure who or how that is done. I just don't really have the tools or time to take it apart. I do have an appt with the dealer to run a diagnostic test next Thurs. I live in middle TN and have searched the internet for a shop that could work on this problem but there appears to be nobody at all which I find very surprising. If any TN peeps on here know of someone please let me know!
We have owned the car for 3 yrs (first Vette) and it came with after-market HU, Borla exhaust and window tint but otherwise is a stock base C6. It does have Onstar and we don't have the subscription so I will see about removing the fuse for that. Any details about doing the parasitic draw test would be appreciated.
We have owned the car for 3 yrs (first Vette) and it came with after-market HU, Borla exhaust and window tint but otherwise is a stock base C6. It does have Onstar and we don't have the subscription so I will see about removing the fuse for that. Any details about doing the parasitic draw test would be appreciated.
I am open to suggestions on how to go about isolating the culprit!
11-27-2021, 01:31 PM
#17
Burning Brakes
There are several threads on diagnosing parasitic draw on the C6 so perform a search and read through them for ideas. I have attached a PDF I pulled from a forum member that may also help with isolating the problem.
Good luck and post back when you finally have a resolution for the problem.
GD
Good luck and post back when you finally have a resolution for the problem.
GD
11-29-2021, 07:37 PM
#18
Cruising
Thread Starter
There are several threads on diagnosing parasitic draw on the C6 so perform a search and read through them for ideas. I have attached a PDF I pulled from a forum member that may also help with isolating the problem.
Good luck and post back when you finally have a resolution for the problem.
GD
Good luck and post back when you finally have a resolution for the problem.
GD
I welcome any thoughts or suggestions here.
12-04-2021, 12:16 PM
#19
Cruising
Thread Starter
Well, the plot thickens. I started testing for battery drain this weekend. My DVM was rated for 10A and I blew both fuses in the meter (10a & 200ma). I had to borrow my neighbor's meter to verify the fuses were blown. So I ordered a new 20a rated meter as it was only a few bucks more than trying to order packs of 10a and 200ma fuses. It arrived today and my initial reading was about 1.5a but it went down to about 0.8a after a few seconds. I assume that was the car's electronics detecting the meter. At some point after that I was testing again and got no reading at all. I grabbed my neighbor's meter and checked my new meter and sure enough the fuses were blown. My timeline/order of things is getting a little blurry for me but I do know that I realized the passenger door was not fully close but not sure if that was before or after the 0.8a reading. So I just ordered a pack of 20a fuses that will be here on Wed 12/1 so I can do further troubleshooting. I am beginning to strongly suspect that I don't have a module draining the battery but perhaps a corroded connector somewhere possibly creating a short in the circuit. I was very careful to do my testing with the meter in series between the negative cable and the negative post of the battery with my red lead being on the negative cable and black lead on the post. And yes, the leads were in the correct ports of the meter for testing 20a current.
I welcome any thoughts or suggestions here.
I welcome any thoughts or suggestions here.
Pulled each of these individually and current draw never changed for each test.
1. Onstar
2. Tele Sw / Mem seat module
3. Driv Dr Sw
4. Ign Sw / Intr Sens
5. TPA fuses
Suggestions on what to try next? There are several more fuses in the passenger floor fuse compartment but from what I have read, they are not part of the BATT5 circuit.
NOTE: I ended up replacing both battery terminals too as part of this process because earlier this week I was getting very erratic readings and decided the factory terminals had to go. They have been replaced with Fastronix terminals and seem to be very nice.
12-05-2021, 03:14 AM
#20
Burning Brakes
You have to open the key fob and clean the printed circuit board copper contacts. The fob will come back to life and work perfectly. Search the forum if you need detailed instructions. Try it and let us know.