Ok - this is fun for anyone watching, but not so much fun to have. This happened after I let the battery run down after not using the car for 6 months. I had to replace the battery.

Car: C6 2007 coupe LS2 Grand Sport

Issue: Both doors will not open

When you press the inside button, the window will drop (on both sides), and the LED will flash on the door, but that's it. From the outside, if you press the release, nothing happens.
If I press the lock/ unlock on any fob, the headlights turn on/ off, and I can start the car if I get in. Pressing the lock/unlock on the door in the car does not change anything. The windows can be put up and down. I have three fobs; all will let the car start. No fob will pop the message of "No fob found".
The fun part is that if you disconnect the battery and re-connect, both doors open simultaneously. (which has me going, "The motors are ok in the door locks")

My first thought was BCM or the RCDLR module, so I got junkyard replacements - I replaced the BCM first - No Change, then the RCDLR (as you expect, it couldn't find a fob, I did the key replacement process (5 presses with the key under the licence plate method). I couldn't get Tech2 to add the keys, which may be a user error.
Have replaced on drivers door the inside and outside door switches.

The only fault on the Tech2 is a comms lost to trans, which it has had for years off and on. It clears but will return if you try to start it with a low battery.

It is unlikely that both door modules failed at the same time. It "feels" more like a mode than a fault.

I would run it down to a dealer, but being in Aussie, the closest is 6000 miles away and a boat trip.
I left it overnight with the battery disconnected (hence, I know the doors open when you reconnect the battery, which, if you disconnect for 10 seconds, both doors always open). I thought, yeah - problem fixed, jumped in, drove around the block then couldn't get out without pulling the manual release.

Any clues would be gladly taken. I've got a spare window actuator on order, but this is me just randomly replacing anything related (but I think it is also unlikely that two failed at once).

 

I find it odd that both actuators went out at the same time, but C6s are known for random gremlins like that. I experienced everything you discussed 'When you press the inside button, the window will drop (on both sides), and the LED will flash on the door, but that's it. From the outside, if you press the release, nothing happens.' What worked for me is I replaced the touch pad on both sides and both door lock actuators. Honestly, from being where you are at right now just replace those components even if you don't think there is anything wrong with them so you can get back to enjoying your Corvette problem free. I bought everything off amazon (touchpads and actuators) for both sides for around $100 USD and I would do it again without a doubt, the replacement job is fairly easy.

 

Lets do a hard reset on all the modules in the car and see if that solves the problem.

Remove the battery cables from the battery, and away from the battery, touch the cables to each other a few times.
This will safely drain all the power from the modules in the car.

Now connect the positive cable first to the battery and tighten down the 10mm nut, then when you go to connect the negative cable to the battery, one clean shot down and on, so it powers up the modules and they stay powered up as you tighten the 10mm nut to secure it in the end.

I bring this up, since the lower battery when you tried to start the car low voltage glitch the modules, and if you don't either touch the cables away from the battery to drain the modules, or did not allow the car to be off the battery long enough for the modules to voltage drain all the way down, then even with new charge battery in play, modules can still be low voltage glitched.

 

Thanks, OGVette. I have replaced on the driver's door, the inside switch, and the outside pad. I had read the other posts and some of the fun others had - and both are easy-access parts. This didn't fix it.

I found this in a Google search:

Diagnostic Steps:

Door Latch Inoperative from All Door Handle Switches

Ignition OFF, disconnect the harness connector at the inoperative door latch.
Connect a test lamp between latch control circuit and ground.
Ignition ON, activate the appropriate interior door handle switch. The test lamp should turn ON when activating the door handle switch.
⇒ If the test lamp is always OFF, test the latch control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ If the test lamp is always ON, test the latch control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

Connect a test lamp between the latch control circuit and latch enable control circuit.
Ignition ON, activate the appropriate interior door handle switch. The test lamp should turn ON when activating the door handle switch.
⇒ If the test lamp is always ON, test the latch enable control circuit for a short to ground. If the circuit tests normal, replace the RCDLR.

⇒ If the test lamp is always OFF, test the latch enable control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the RCDLR.

If all circuits test normal, test or replace the appropriate door latch.


This has me thinking I might have a wiring issue or two dead door latchs - i'e replaced the BCM and the RCDLR but cant get passed the fact the doors pop open if you unplug and plug in the battery. I did use a junkyard bcm - there is that 1% chance that the both have the same issue - but new ones seem harder to find.

 

I hope you get it sorted out very soon.

 

Hmm - I just unplugged the battery overnight (I took it out and stuck it on a charger to ensure it was 100% charged). I didn't short the power cables together. I'll give that a shot. I've pulled off the battery; I'll short them in the morning before heading out to the office.

 

About that replacement battery. Did you make sure it was charged right up before you used it? They do self discharge, and as a point of reference, I just had to go through the process of replacing the battery yet again on our daily. It’s the 3rd Everready AGM in about 30 months (first 2 replaced free from Costco) and even though it’s got a date sticker on it of 12/24, it needed about 24 hours on the 2A maintainer before the green light lit up on the maintainer. That seems to me that it was maybe 50% charged, and in the case of our Corvettes, you know how they don’t respond well to low voltage. Now that you’ve had the charger on it, maybe that will fix the problem, but unless you took a voltage reading before, you won’t know if the problem was low voltage or if you needed to bleed down and reboot the modules.

 

After module reset, put a tech 2 on the car,and see if you can activate the door latches with it. If you can, then tells you that problem is switches to BCM, and not BCM down line to door latch activators instead.

 

Yes, it was fully charged before I put it in - they seem to only charge them 60% for storage here as well - Like you, I put it on a charger overnight before putting it in the car. I also put it back on the charger overnight while grounding the two leads to ensure no power was left in the vehicle. It seems to have made no difference. I'm getting the feeling that I have a ground issue, that is, with no facts to back it up with. Having replaced the BCM and RCDLR, it only points to the wiring or door latch. I'll change the window module (I ordered one for spare, which came in this morning) only because of the handful of straw it came in with that I can cling to. I think it may need a bigger hammer if that doesn't fix it.

I asked a local shop how much it would cost to fit a new wiring loom (assuming I can get one), and they were honest enough to say it would be around the same price as a new C8. I'm happy to throw small change at it, but their labour costs seemed a bit over the top. So, it would fall into another DIY event. I love this car; I have this and a heavily played-with C4, which is faster but is showing its age in styling. I've had both from new. This is the first issue that is not user-related.

 

That is a great Idea - I didn't think to try that. I was reading codes, I didn't think to get the tech2 to send commands. I'll give that a hit tonight.

 

When I quickly read your first post and you said you could not open the door from the outside and you had a "no comm" with the TCM and "No Fobs Found" I thought that maybe the ECM/TCM/EASY KEY fuse 11 was blown...that fuse is battery power for the ECM,TCM, and RCLDR...with that fuse blown the car will not start anyway even with the FOB in the backup antenna slot in the glovebox so that is probably not the problem...each door module has 2 separate grounds so it wouldn't be that...you said you have a Tech 2 so look and both inputs and outputs...an input would be you pressing the door switch to open it...it is basically a command...an output is you command the door to unlock....I'll have to look into the wiring diagram further...if you just use the Tech 2 to erase codes (which many only do) you have a lot of good diagnostic information available....you may be better off installing your old BCM and RCDLR if they didn't fix your concern....you DON'T need a new wiring loom...if a wiring issue you just need to find that.,,,video below.

 

Ok - Now that we have a good play - I'm more confused.

On Tech II - I can see the door buttons pressed inside and outside on both doors. I can trigger the door to open once only. After being triggered, it shows the door status as "open". I close the door, and it shows "closed", but nothing happens when I repeat the process. The doors don't try to open.

I pulled out a door lock on the driver's side and hooked up a 12v led bulb on the plug where the motor wires are. I put a screwdriver in the loop to close the lock and make it think it had a closed door. The light flashed once brightly the first time, and the lock ½ opened. I couldn't get it to open, (techII read "ajar") so I pushed the lock shut again (techII showed "closed"). The next press of the inside door button there was no flash from the light.

My take on this is it must be a weird mode, or more than one fault in play. I replaced the BCM, and the fault was still there, so I put the old one back, and the replaced the RCDLR - Maybe both have an issue that triggers this (here is that handful of straw again), I'll have a go are replacing both at once.

I did get a door motor module - but have not done anything with it yet, Not looking forward to pulling a door apart. I have taken off the door cards off before to change the Led from red to blue (don't ask - someone sent me the led kit to match the trim, and it looked like a fun thing to do at the time) and I think it unlikely that this the issue, as I can see both switches trigger on both doors

I gave up playing as the weather is a bit hot to be working in the shed (40c or 104F) and it will be that for the next few days.

 

DIC set up, make sure to turn off auto lock to take the RCDLR out of play , since problem may be with just the BCM thinking that car is moving, and it activating the electronic door locks itself. Also, problem may be that you have third party items in the car like LED bulbs, and putting out enough RF noise that is blocking the fog as well.
Note, no real door locks on the car, and it just a BCM function that will not allow the doors actuators to work/get power to unlock the doors, until you press the unlock button again.

And to point out, did you to to press the unlock button the the door, to see if that solved the problem?

 

following. I have had this same issue for a few years now. I have replaced battery, both door pads and both actuators still nothing. Same symptoms, window indexs and i hear the relays clicking, but no opening.

 

I would see if you have any “B” or Body trouble codes stored to give you some direction…seems like changing parts isn’t going to fix this for you.

 

This is the weird thing - no codes are being thrown.

I've replaced almost everything, and she just sits there and says, "Nope - not playing."

I spent hours trying to track wires and measuring resistance and connections, and they all seemed ok. Then I went, ok, I can spend many more hours tracing wires or just rip the loom out and start from a sort of known point.

I ran it down to a local auto shop here - in the hope that the could find something - but after they played with it for a few days that came back to me saying that they couldn't find the fault. They managed to get the passenger door to open normally for a bit, then when they opened the drivers it stopped.

so ... I have gone ok something is just not happy but it feels more like two things play up together.

I have gotten a second hand loom, BCM RCDLC, one door lock and one door window module from a single wreck, with the hope that I can plug and play.

I have started on replacing the body wiring loom - as that is the last bit that hasn't been changed yet. I'm being a bit risk adverse in just plugging in the models to see ( as what ever is the issue make be killing them) The poor old girl looks sad with ½ the dash out.

​​​​​​​

 

Doubt you need the whole body wiring harness but all you would need is to understand how the door lock system works, a wiring diagram, and a factory level scan tool.

 

 

Someone educate me, looking at the Driver Door Module (DDM) what is the diagram symbol ( - at 25, 22, 21, 26? I'm assuming a connector???????

 

25,22,21, and 26 denotes the numbered terminals at the DDM as you can see below…the dashed lines around the DDM means it’s a “partial” view of the module because all of the terminals are not included here…if you look at 22 and 21 and follow it down you will see UA2 in the rectangular box…those are RPO codes and on some diagrams like the information bus you will see a minus symbol and that means WITHOUT that RPO code…UA2 is for exports only and in the DDM module box you will see the word “deadbolt”…on a domestic C6 you will not have those wires on that module…the operation of UA2 is included below…it would take me an hour to explain all the symbols on this wiring diagram…also the connectors are denoted by a “C” with 3 digits…connectors under the hood will be C1XX…connectors in the back of the car will be C4XX…”S” are splices…you will find all this information and locations in Service Information.