Passive unlock not working

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Quinnw1

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C7 Ontario
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I lost the ability to use the passive unlock on my C7 Z06. Neither doors or hatch unlock without pressing the FOB buttons. I did some upgrades over the winter, adding sound deadener to the back hatch floor and inside wheel wells. I also recently added a MGW short throw shifter. Both jobs were done after removing the negative battery terminal, carpet and center console. I have tried everything to no avail. FOB battery brand new Panasonic, tested at over 3 volts. I did see the two antennae for the keyless signals, one in the back hatch with the other electronics, fuses etc. and the one in the center console back between the driver and passenger seats. Both were attached to their wiring harness plugs as I reinstalled everything. I tried setting the DIC back to factory specs and then turning on passive unlock and passive lock, etc. The outside door handle pads work fine, once I unlock the doors with the FOB. Still no go. After searching threads for more ideas, I found nothing. I was wondering if maybe the aluminum backing on the sound absorbing mat may be the culprit, but I don't see why.
Any help would be appreciated, before I head to the dealer.
 
I did not have this issue last year when I did a complete interior removal and sound deadener/heat shielding install , but I do remember reading about similar problems after a battery disconnect ( I also had battery disconnected, but no issues,other than resetting of windows) , keep Googling problem and check the American corvette websites , like I say I remember reading of this issue or like issue and just being a matter of doing steps in the right order to get all working properly again. Best of luck with issue.
 
Quinnw1 said:
I lost the ability to use the passive unlock on my C7 Z06. Neither doors or hatch unlock without pressing the FOB buttons. I did some upgrades over the winter, adding sound deadener to the back hatch floor and inside wheel wells. I also recently added a MGW short throw shifter. Both jobs were done after removing the negative battery terminal, carpet and center console. I have tried everything to no avail. FOB battery brand new Panasonic, tested at over 3 volts. I did see the two antennae for the keyless signals, one in the back hatch with the other electronics, fuses etc. and the one in the center console back between the driver and passenger seats. Both were attached to their wiring harness plugs as I reinstalled everything. I tried setting the DIC back to factory specs and then turning on passive unlock and passive lock, etc. The outside door handle pads work fine, once I unlock the doors with the FOB. Still no go. After searching threads for more ideas, I found nothing. I was wondering if maybe the aluminum backing on the sound absorbing mat may be the culprit, but I don't see why.
Any help would be appreciated, before I head to the dealer.
Click to expand...
Sounds like you've done pretty much everything reasonable to diagnose the problem. I don't believe that your recent modifications would cause the problem that you're experiencing.

My suggestions, at this point, would be to make sure that the vehicles battery is fully charged. Then remove the negative battery cable, again, for 15 minutes, reattach it and see if that makes a difference. You will have to reindex the windows. This should not change your DIC settings but check just in case. Then, change the battery in the second FOB and try that if you have not already done so. Lastly, assuming the battery is the original OEM unit, have it load tested by a competent, trusted C7 service tech. I see that your car is a 2019 and you may think that the battery is good but minor electrical glitches are usually the first indication that the battery is starting to fail even if it appears to be functioning properly. C7 batteries are good for about 4 to 5 years of normal service when maintained properly. After that, they have a tendency to fail and can do so slowly, over time, or can go bad within a short period. Even if you have replaced the vehicles battery recently, have it load tested just to make sure it's okay.

My GS is also a 2019 but it was built in February, 2018 so it's over 4 years of age now. I'm keeping a close eye on the battery as I'm anticipating possible failure this season. If I get through this year, I'll replace it next spring as a precautionary measure.

Good luck.

Best regards
Ross
 
theboss said:
I wonder if there is a setting for that, on many car you can set auto lock, unlock only one door and some other different options,
Click to expand...
There is a range of settings for passive or not passive lock/unlock. I have mine set to lock as soon as I walk away from the car and unlock when I come to 3 feet away from the car. I assumed he had tried re-setting for this.
 
Yes. Reset to factory several times then back to remote unlock or passive unlock and passive lock after all doors are closed. The passive lock works fine but not the passive unlock?
 
Quinnw1 said:
Yes. Reset to factory several times then back to remote unlock or passive unlock and passive lock after all doors are closed. The passive lock works fine but not the passive unlock?
Click to expand...

Well I wish you luck with your issue. Perhaps take a drive to a Chevy dealer near you and have a quick chat with the service dept. They may have encountered this before and tell you how to fix.... Over the next few days I'll pop into the dealership that does my servicing as my remote start function stopped working.... they wont charge to provide suggestions. Good luck
 
Well, no dice. Took everything apart again to check the electrical connectors, including the 2 FOB antennae to make sure they were seated and connected properly. Removed both battery terminals and touched them together to delete the energy in the car overnight. Funny thing, I did not have to re index the windows or update the personal settings, including radio presets. I did however loose the TPMS pressure readings for the tires and my GPS calibration. I now have a "Service the Remote Start System" in the dash DIC? My car is an M7. I don't have a remote start option? Off to the dealer I go.
 
You've done all that you can to this point. Little electrical gremlins like this are so often related to a failing battery, you never did confirm if the one in your vehicle is the original or not. Anyway, hopefully you have a competent service facility that can resolve this issue for you. Best of luck.
 

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