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DTC B3120

DTC B3120

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 B3120 02

Keyless Entry Antenna 2 Short to Ground

DTC B3120 05

Keyless Entry Antenna 2 High Voltage/Open

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Keyless Entry Antenna - Passenger Door Signal

B3120 02

B3120 05

B3120 05

-

Keyless Entry Antenna - Passenger Door Low Reference

-

B3120 05

-

-



Circuit/System Description

The passenger front door handle antenna is located in the passenger front door handle assembly and is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with locked doors is approached with a keyless entry transmitter and the exterior door handle is activated, the keyless entry antenna communicates with the keyless entry control module.

Conditions for Running the DTC




• The touch pad in the passenger front door handle is touched within 15 min of any door ajar status changing.

• The front or rear door handle on the driver side is pulled.

• The scan tool activates a device control function to simulate the above actions.


Conditions for Setting the DTC

B3120 02

The keyless entry control module detects a short to ground on the passenger front door keyless entry antenna circuit.

B3120 05

The keyless entry control module detects a short to B+ or an open circuit on the passenger door keyless entry antenna circuit.

Action Taken When the DTC Sets

Doors will not unlock when front passenger handle or corresponding rear handle is pulled. Doors will not lock with passenger touch pad.

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 40 malfunction-free ignition cycles.


Reference Information

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Keyless Entry System Description and Operation (without ATH) Keyless Entry System Description and Operation (with ATH)

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Note

Verify that the pins are correct for all of the antennas. Make sure to fix any problems with the interior antennas first, before proceeding to the following diagnostics below regarding the exterior antennas. If any of the interior antenna DTCs B3122, B3123, B3124 is set, the diagnostic procedures on the exterior antennas will not work.



1. Ignition OFF, disconnect the harness connector at the T10N Keyless Entry Antenna - Passenger Door Handle.

2. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal 1 and ground.

3. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal replace the K84 Keyless Entry Control Module.

4. Verify a test lamp does not illuminate between the low reference circuit terminal 2 and ground.

5. If the test lamp illuminates, test the low reference circuit for a short to voltage. If the circuit tests normal replace the K84 Keyless Entry Control Module.

6. Connect a DMM, set to capture alternating voltage using the MIN MAX function, between the signal circuit terminal 1 and ground.

Note

Use DC voltage because comparing to vehicle ground.


7. Activate the antenna in the driver's door handle by pulling the handle. Only the antenna is disconnected, not the microswitch which is mounted on another connector. After pressing the MIN/MAX button looking for any voltage, verify the DMM captured a DC voltage signal.

8. If the DC voltage was not captured, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the K84 Keyless Entry Control Module.

9. Connect a DMM, set to capture alternating voltage using the MIN MAX function, between the signal circuit terminal 1 and the low reference circuit terminal 2.

Note

May have to use AC instead of DC voltage for low reference circuit. This increases sensitivity of voltage measurements for this test. It also increases sensitive to outside interference as well. Pay careful attention when the handle is pulled for this test.


10. Activate the antenna in the driver's door handle by pulling the handle. Only the antenna is disconnected, not the microswitch which is mounted on another connector. After pressing the MIN/MAX button looking for any voltage, verify the DMM captured a DC or AC voltage signal.

11. If a DC or AC voltage was not captured, test the low reference circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the K84 Keyless Entry Control Module.

12. If all circuits test normal, replace the T10N Keyless Entry Antenna - Passenger Door Handle. Clear DTCs and then pull the driver's door handle and check for any DTCs. If DTC B3120 returns, replace the K84 keyless entry control unit


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Front Side Door Outside Handle Replacement (Base)

• Control Module References for keyless entry control module replacement, setup and programming