Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B3121 02: Keyless Entry Antenna 3 Short to GroundDTC B3121 05: Keyless Entry Antenna 3 High Voltage/Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Rear Fascia --Keyless Entry Antenna Signal | B3121 02 | B3121 05 | B3121 05 | -- |
Rear Fascia --Keyless Entry Antenna Signal | -- | B3121 05 | -- | -- |
Circuit/System Description
The rear compartment keyless entry antenna is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with a closed rear compartment lid is approached with a keyless entry transmitter, known as an user identification device, and the rear compartment lid release switch is pressed, the keyless entry antenna transmitter broadcasts a challenge to the transmitter in an approximate 1 meter range. If the response from the transmitter via radio frequency is valid, the latched rear compartment will be passively unlocked/unlatched, allowing the rear compartment area to be opened.
Conditions for Running the DTC
The handle or touch pad used to open the rear closure is activated.
Conditions for Setting the DTC
B3121 02
The keyless entry control module detects a short to ground on the rear fascia keyless entry antenna circuit.
B3121 05
The keyless entry control module detects a short to B+ or an open on the rear fascia keyless entry antenna circuit.
Action Taken When the DTC Sets
No action is taken
Conditions for Clearing the DTC
| • | A current DTC will clear when the conditions for setting the DTC are no longer present |
| • | A history DTC will clear after 50 malfunction free ignition cycles |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Keyless Entry System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the T10E rear compartment keyless entry antenna.
- Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal A and ground.
- Connect a DMM, set to capture AC voltage using the MIN MAX function, between the signal circuit terminal A and the low reference circuit terminal B.
- Press the rear compartment lid release switch. Verify the DMM captured an AC voltage signal.
- If all circuits test normal, test or replace the T10E rear compartment keyless entry antenna.
| ⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the keyless entry control module. |
| ⇒ | If an AC voltage was not captured, test the signal circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the keyless entry control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for keyless entry control module replacement, setup, and programming
