B3121

DTC B3121

Circuit Description

The keyless entry antenna - rear compartment is located in the rear compartment area and is used as a short range low frequency (LF) antenna. As a vehicle with a closed rear compartment lid is approached with a keyless entry transmitter and the exterior rear compartment lid release pad is pressed, the keyless entry antenna broadcasts a challenge to the transmitter in an approximate 1 meter range. If the response from the transmitter via radio frequency (RF) is valid, the latched rear compartment will be passively unlatched, allowing the rear compartment lid to be opened.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3121 Keyless Entry Antenna 3 Performance






Conditions for Setting the DTC

The remote control door lock receiver (RCDLR) will set this DTC during antenna authentication if the keyless entry antenna - rear compartment is open, shorted to battery, or shorted to ground. The RCDLR can only set a DTC when it is the vehicle system voltage is between 9-16 volts.

Action Taken When the DTC Sets

The RCDLR will set and store a DTC B3121.

Conditions for Clearing the DTC

* The RCDLR no longer detects a open, short to power, or short to ground on the antenna circuit.
* The use of a scan tool

Test Description

Step 1 - Step 9:

Step 10 - Step 12:

The numbers below refer to the step numbers on the diagnostic table.
2. Verifies that DTC B3121 is a current DTC.
3. Verifies that the exterior rear compartment lid release pad is operating properly. A valid input from the lid release pad is required by the RCDLR to authenticate the antenna.
4. Testing for power and ground to the keyless entry antenna.