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 locked rear compartment will be passively unlocked/unlatched and allow the rear compartment to be opened.
This diagnostic procedure supports the following DTC:
DTC B3121 Keyless Entry Antenna 3 Performance
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .
DTC Symptom | DTC Symptom Descriptor |
---|---|
02 | Short to Ground |
05 | Short to Battery or Open |
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 the vehicle system voltage is between 9-16 volts.
The RCDLR will set and store a DTC B3121.
• | The RCDLR no longer detects a open, short to power, or short to ground on the antenna circuit. |
• | Use the scan tool. |
The numbers below refer to the step numbers on the diagnostic table.
Check to see if DTC B3121 is current.
Verifies that the exterior rear compartment lid release pad is operating properly. A valid input from the rear compartment release pad is required by the RCDLR to authenticate the antenna.
Testing for power and ground to the keyless entry antenna.
Step | Action | Yes | No | ||||
---|---|---|---|---|---|---|---|
Schematic Reference: Remote Function Schematics Connector End View Reference: Remote Function Connector End Views | |||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||
Important: To achieve service by pass mode, key ON, engine OFF, a programmed transmitter must be detected within the passenger compartment of the vehicle.
Does the scan tool display DTC B3121 as a current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | |||||
Does the trunk release switch state display INACTIVE? | Go to Step 4 | ||||||
Important:
Was an AC voltage signal captured on the DMM? | Go to Step 7 | Go to Step 5 | |||||
5 | Test both the keyless entry antenna signal and low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 6 | ||||
6 | Inspect for poor connections at the RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 8 | ||||
7 | Inspect for poor connections at the keyless entry antenna - rear compartment. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | ||||
8 | Test the keyless entry antenna signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | ||||
9 | Replace the RCDLR. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- | ||||
10 | Test both the keyless entry antenna signal and low reference circuit for a short to power. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | ||||
11 | Replace the keyless entry antenna - rear compartment. Refer to Ignition Lock Key Transmitter Antenna Replacement - Rear Compartment . Did you complete the replacement? | Go to Step 12 | -- | ||||
12 |
Does the DTC set again? | Go to Step 3 | System OK |