My driver door won't unlock without using the fob key. Passenger side is fine. Went through the settings and set for both to unlock. Replaced touchpad and latch mechanism. Scan is B3119, keyless entry antenna 1 performance. Could the antenna fail or is there a fuse for that?

 

The Keyless entry left antenna, located in the left hand B pillar and is used as a short range low frequency transmitter. As a vehicle with locked doors is approached with a key FOB, and the exterior door pad is pressed, the keyless entry antenna transmitter broadcasts a challenge to the key fob in an approximately 1 meter range. If the response from the key fob via Radio Frequency is valid, the locked door will be passively unlocked/unlatched and allow the door to be open.
If you get a DTC B3119 code(Keyless Entry Antenna 1 Performance) the following conditions have to be met.
The remote control door lock receiver (RCDLR) will set this DTC during antenna activation if the keyless entry antenna -left is open, shorted to battery or shorted to ground and an authentication occurs. The DTC can only be set if the main battery voltage is between 9-16 volts.

TESTING: Have to Car ignition switch to ON- Car not running.
The voltage signal sent by the RCDLR to the passive antenna is a AC voltage signal. The Digital Multi Meter (DMM) must be set on AC voltage setting to record the voltage pulse to the passive antenna.
Important: Use a DMM to record the voltage pulse using the MIN MAX setting to capture the AC voltage pulse to the passive antenna.
IMPORTANT: The exterior door pad must be pressed to produce the voltage pulse to the passive antenna
1) Disconnect the keyless entry antenna - left at the B pillar
2) With the DMM measure/capture for an an AC voltage signal between the keyless entry antenna power circuit and the ground circuit.
Depending upon the results. If voltage was recorded, inspect the antenna for poor connection. If a poor connection or wire is found, see if the DTC will clear.
If no power is recorded test power and ground circuit for an open circuit.
If a open circuit is suspected, then check the connec tor wires
If all seems Ok at the connectors/wires, then it's possible that the antenna needs to be replaced.

Access to the B pillar Antenna
1) Remove the left lock pillar trim
2) remove the rear window trim panel
3) disconnect the antenna wire lead from the antenna
4) pull on the antenna to disengage the antenna from the retaining bracket




Hope this guides you in the right direction.

 

Great information! Thanks so much. Been chasing this problem for awhile. Project for this weekend.

 

Good luck with your troubleshooting.
Here is part of the schematic for the Keyless antenna system/power source

 

I finally got access to the antenna. I first tried removing the inner panels to access it but couldn't see it. I started removing the rear quarter panel but found when unbolting the enclosure for the gas cap the antenna was within reach of the opening. It took a couple minutes to pull the old antenna and replace it. Unlock without touching the fob WORKS.
Antenna is 25888495 $15.

 

This is great information... I love this forum !

 

Congrats on getting to the antenna easily, and replacing it to fix the issue.
Always nice to hear success stories.

Take Care