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 Performance Short to GroundDTC B3121 05: Keyless Entry Antenna 3 Performance Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Keyless Entry Antenna - Signal (4) | B3119 02 | B3119 05 | B3119 05 | -- |
Keyless Entry Antenna - Low Reference (4) | -- | B3119 05 | -- | -- |
Keyless Entry Antenna - Signal (5) | B3120 02 | B3120 05 | B3120 05 | -- |
Keyless Entry Antenna - Low Reference (5) | -- | B3120 05 | -- | -- |
Keyless Entry Antenna - Signal (3) | B3121 02 | B3121 05 | B3121 05 | -- |
Keyless Entry Antenna - Low Reference (3) | -- | B3121 05 | -- | -- |
Keyless Entry Antenna - Signal (2) | B3123 02 | B3123 04 | B3123 04 | -- |
Keyless Entry Antenna - Low Reference (2) | -- | B3123 04 | -- | -- |
Keyless Entry Antenna - Signal (1) | B3123 02 | B3123 04 | B3123 04 | -- |
Keyless Entry Antenna - Low Reference (1) | -- | B3123 04 | -- | -- |
Keyless Entry Active Antenna Supply Voltage | B3122 04 | B3122 04 | B3122 04 | -- |
Keyless Entry Active Antenna Data Signal | B3122 04 | B3122 04 | B3122 04 | -- |
Keyless Entry Active Antenna Clock Signal | B3122 04 | B3122 04 | B3122 04 | -- |
Keyless Entry Active Antenna Low Reference | -- | B3122 04 | -- | -- |
Circuit/System Description
The rear compartment keyless entry antenna is used as a short range low frequency (LF) transmitter. As a vehicle with a closed rear compartment lid is approached with a key fob and the rear compartment lid release switch is pressed, the keyless entry antenna transmitter broadcasts a challenge to the key fob in an approximate 1 meter range. If the response from the key fob via radio frequency (RF) is valid, the latched rear compartment will be passively unlocked/unlatched, allowing the rear compartment area to be opened.
Conditions for Running the DTC
A transmitter validation is requested.
Conditions for Setting the DTC
An improper voltage level is seen on the keyless entry antenna - signal 3 circuit.
Action Taken When the DTC Sets
The rear compartment keyless entry antenna is ignored.
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 rear compartment keyless entry antenna.
- Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal A and ground.
- Install a DMM between the signal circuit terminal A and the low reference circuit terminal B. Set the DMM to capture AC voltage using the MIN MAX function.
- Press the rear compartment lid release switch. Verify the DMM captured an AC voltage signal.
- If all circuits test normal, test or replace the 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 RCDLR. |
| ⇒ | 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 RCDLR. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for RCDLR replacement, setup, and programming |
