# Nissan Sentra Key Error Question



## asyok1337 (5 mo ago)

Hey! 
I have a Nissan Sentra from 2019.
It is showing a key system error.
The Key is fine (was checked by a dealer and I drove for 1k miles with this thing), and the battery was replaced recently.
One guy connected a computer to it and it showed an antenna error. 


The car was crashed into the passenger side and totaled. The previous owner replaced two doors.
Now the passenger door doesn’t have a button to open the car (but the drivers has it).

My guess is it’s because the passenger door had an antenna and now it doesn’t. 
I would guess erasing errors won’t help. How should I fix it?


----------



## VStar650CL (Nov 12, 2020)

That's actually a common problem with body shop repairs. They probably used a junkyard door from a car with a lollipop key and not an I-key, so now the door has the wrong wiring harness and a handle with no antenna. The antenna DTC you're getting is because the BCM is seeing an open circuit where the antenna is supposed to be. To fix it right you need to replace the door harness and the handle with the correct parts. However, one thing I've never tried but that should work in theory is using a resistor with the same value as the antenna coil to bridge the antenna wires in the Main Harness and fool the BCM. To do that you'll need to access the connector for the lefthand antenna and ohm through it to find the needed resistor value. Then you'll need to access the umbilical connector where the righthand door connects to the car and bridge the Main Harness side of the antenna wires with a similar resistance. Those wires will be a Brown in position 40 and a Yellow in position 41.


----------



## asyok1337 (5 mo ago)

VStar650CL said:


> That's actually a common problem with body shop repairs. They probably used a junkyard door from a car with a lollipop key and not an I-key, so now the door has the wrong wiring harness and a handle with no antenna. The antenna DTC you're getting is because the BCM is seeing an open circuit where the antenna is supposed to be. To fix it right you need to replace the door harness and the handle with the correct parts. However, one thing I've never tried but that should work in theory is using a resistor with the same value as the antenna coil to bridge the antenna wires in the Main Harness and fool the BCM. To do that you'll need to access the connector for the lefthand antenna and ohm through it to find the needed resistor value. Then you'll need to access the umbilical connector where the righthand door connects to the car and bridge the Main Harness side of the antenna wires with a similar resistance. Those wires will be a Brown in position 40 and a Yellow in position 41.





VStar650CL said:


> That's actually a common problem with body shop repairs. They probably used a junkyard door from a car with a lollipop key and not an I-key, so now the door has the wrong wiring harness and a handle with no antenna. The antenna DTC you're getting is because the BCM is seeing an open circuit where the antenna is supposed to be. To fix it right you need to replace the door harness and the handle with the correct parts. However, one thing I've never tried but that should work in theory is using a resistor with the same value as the antenna coil to bridge the antenna wires in the Main Harness and fool the BCM. To do that you'll need to access the connector for the lefthand antenna and ohm through it to find the needed resistor value. Then you'll need to access the umbilical connector where the righthand door connects to the car and bridge the Main Harness side of the antenna wires with a similar resistance. Those wires will be a Brown in position 40 and a Yellow in position 41.


Thank you so much for your answer!
I visited many mechanics in my town and they all do not really deal with such problems. It would be pretty expensive to go to the dealership…
Do you think it’s possible to replace the antenna by myself? I don’t really have an experience with actual repair work.
Or could be the way to erase the error or maybe do something physically so it will stop looking for that antenna?


----------



## VStar650CL (Nov 12, 2020)

asyok1337 said:


> Or could be the way to erase the error or maybe do something physically so it will stop looking for that antenna?


Not except for the way I suggested. The BCM expects to see continuity through something, at least a resistor if not an antenna.



asyok1337 said:


> Do you think it’s possible to replace the antenna by myself? I don’t really have an experience with actual repair work.


The handle and harness aren't rocket science to replace, but it would be a _very_ tricky job for someone with zero experience. If you want to try the resistor thing, I'd suggest printing out my answer and taking it to a good general mechanic. Armed with the correct info about what to do, anyone competent can handle that. Lack of detailed vehicle information is the reason most general shops don't want to deal with that sort of issue. Radio Shack isn't around anymore, but buy a cheap resistor assortment off eBay in advance so the technician will have something to bridge the open righthand terminals once he measures the left side antenna and knows the right value.


----------

