B3120
DTC B3120
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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/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 pulled, the keyless entry control module communicates with the passenger front door handle keyless entry antenna.
Conditions for Running the DTC
* The touch pad in the passenger front door handle is touched within 15 minutes of the last change of door ajar status for any door.
* The front or rear door handle on the passenger 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 on the passenger front 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 (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Keyless Entry System Description and Operation (without ATH) (Keyless Entry System Description and Operation (Without ATH))Keyless Entry System Description and Operation (with ATH) (Keyless Entry System Description and Operation (With ATH))
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) 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 passenger front door handle antenna.
2. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal 1, connector on vehicle side, and vehicle ground and also does not illuminate between low reference signal circuit terminal 2, connector on vehicle side, and vehicle ground.
• If the test lamp illuminates, disconnect the connector at the keyless entry control module, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the keyless entry control module.
3. Connect a DMM, set to capture DC voltage using the MIN MAX function, between the signal circuit terminal 1 and vehicle ground.
Note: Use DC voltage because comparing to vehicle ground.
4. Activate the passenger front door handle antenna by manually pulling the passenger front door handle, only the antenna is disconnected not the micro switch, that is on a different connector. After pressing the min/max button looking for any voltage, verify the DMM captured a DC voltage signal.
• 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 keyless entry control module.
5. Connect a DMM, set to capture DC voltage using the MIN MAX function, between the low reference circuit terminal 2 and vehicle ground.
6. Activate the passenger front door handle antenna by manually pulling the passenger front door handle, only the antenna is disconnect not the micro switch, that is on a different connector. After hitting the min/max button looking for any voltage, verify the DMM captured a DC voltage signal.
• If the DC 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 keyless entry control module.
• Clear DTCs then pull passenger front door handle and check for DTCs again.
• If DTC B3120 returns replace the T10N passenger front door handle. Clear DTCs again then pull the passenger front door handle and check for DTCs.
• --> If DTC B3120 returns, replace the keyless entry control module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Side Door Outside Handle Replacement (Base) (Service and Repair)Front Side Door Outside Handle Replacement (ATH) (Service and Repair)
* Control Module References (Programming and Relearning) for keyless entry control module replacement, setup, and programming