Cruze

DTC B3120

The passenger front door handle aerial 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 aerial.

B3120 02

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

B3120 05

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

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

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Keyless Entry System Description and Operation : with ATH → without ATH

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

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

1. Ignition OFF, disconnect the harness connector at the T10N passenger front door handle aerial.
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 aerial by manually pulling the passenger front door handle, only the aerial 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 aerial by manually pulling the passenger front door handle, only the aerial 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.

7. 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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.