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Discussion Starter #1
So i just bought a 2018 impala lt with 6 cylinder engine.

It says "Service Key less Entry" when ever i get in and turn it on, also, the buttons on the exterior handles will not work. Don't want to take it to a service department just for them to start replacing simple plug in electronic modules. Read about there being a box in the trunk that may have an antenna on it, but haven't checked that yet.

Thanks.
 

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So i just bought a 2018 impala lt with 6 cylinder engine.

It says "Service Key less Entry" when ever i get in and turn it on, also, the buttons on the exterior handles will not work. Don't want to take it to a service department just for them to start replacing simple plug in electronic modules. Read about there being a box in the trunk that may have an antenna on it, but haven't checked that yet.

Thanks.
I'd start by checking fuse 29 in the underhood fuse box.

BTW, does your key fob still work? If so, then the antenna can be ruled out.

HTH.
Doug

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Discussion Starter #3
I'd start by checking fuse 29 in the underhood fuse box.

BTW, does your key fob still work? If so, then the antenna can be ruled out.

HTH.
Doug

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yea. it still works. i will try that out. thanks for the help. will let you know.
 

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Discussion Starter #4
I'd start by checking fuse 29 in the underhood fuse box.

BTW, does your key fob still work? If so, then the antenna can be ruled out.

HTH.
Doug

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So. did the 29 fuse(5amp) and its good. Even checked others that i thought may be it. but they are all good.
 

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So. did the 29 fuse(5amp) and its good. Even checked others that i thought may be it. but they are all good.
Sorry for the delay in responding.

I'm not sure what step I would take next. I suppose getting the codes read would be a good start.

If no codes, my next step would probably be to pull back the rubber boot in the driver's door jamb looking for a broken wire. Since that door gets opened and closed the most, that's where a break is most likely to occur.

It's kind of a pain to dig into the boot. Once you pull it back, you have to remove the sheath from the wire bundle, and then deal with the sticky coating beneath it. Plus, it helps to have a diagram showing the particular wires of interest. If I can find one, I'll post it back later.

Doug

[Edit] I've attached a couple drawings for the keyless entry. If you can get a code read, that would be great. The second drawing (...4356115.pdf) shows a twisted pair of wires, VT and VT/GY (violet/gray) going to the driver's door handle antenna module. If I had to pick a starting point, I might focus on them.

That said, you report "the buttons on the exterior handles will not work", but I wouldn't expect one malfunctioning keyless entry door handle antenna to result in none of the exterior buttons working, so I'll do some more digging.

In the mean time, getting a code would really help.

Doug

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Attached is one more drawing. It shows each door handle having a one-wire serial bus back to the "keyless entry control module" (KECM). As before, if one of these is wonky, I would expect it to be the wire in the driver's door, but, as before, I cannot see that bringing down the entire keyless entry system. It would affect the driver's door only, I expect. (Altho I've seen some bad system design where that could happen :( )

So, with none of these door handle switches working, I would expect the issue to be up a level in the hierarchy - somewhere in the KECM or the power or ground wires for it.

The fuse has been checked, so, without any codes, about all that can be done is to find and inspect the KECM to see if there's a loose wire feeding it.

If you dig into this, let us know what you find.

BTW, I don't have any 2018 drawings, but the 2017 drawings I've attached should be the same.

Doug

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Discussion Starter #8
Thanks Doug. I will for sure let you know what i come up with. My wife drives it and i work long hours so it may be a little bit of time before I can get around to doing these.

But I thank you a lot. She is saying to take it to a dealer but I have met our nearest ones service department and I will pass on someone doing these things you have listed and charging god knows how much for it.
 
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