B3123
DTC B3123
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 B3123 02
- Keyless Entry Antenna 5 Short to Ground
DTC B3123 05
- Keyless Entry Antenna 5 High Voltage/Open
Diagnostic Fault Information
Circuit/System Description
The rear center console antenna is located in rear of the center console assembly and is used to establish low frequency communications with the keyless entry transmitter. When the driver attempts to change the ignition status of the vehicle, the keyless entry control module communicates with the rear center console antenna.
Conditions for Running the DTC
* The touch pad in the driver door or passenger door handle is touched within 15 minutes of any door ajar status changing.
* The last door becomes closed.
* Pressing the start/stop switch.
Conditions for Setting the DTC
B3123 02
The keyless entry control module detects a short to ground on the rear center console keyless entry antenna signal circuit.
B3123 05
The keyless entry control module detects a short to B+ or an open on the rear center console keyless entry antenna signal circuit.
Action Taken When the DTC Sets
Vehicle will not detect the transmitter in some locations inside the vehicle. If the transmitter is not detected then vehicle will not change ignition modes when start/stop button is pressed.
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 [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (D6I)
Description and Operation
Keyless Entry System Description and Operation (with BTM) Keyless Entry System Description and Operation (with BTM)Keyless Entry System Description and Operation (without BTM) Keyless Entry System Description and Operation (without BTM)
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 Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the T10K center console rear keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground.
• If 1 V or greater
1. Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K84 keyless entry control module.
• If less than 1 V
Note: When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 000.0 V.
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
5. Verify the MAX voltage captured by the DMM is greater than 1 V.
• If 1 V or less
1. Ignition OFF, disconnect the harness connector at the K84 keyless entry control module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohm in the signal circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K84 keyless entry control module.
• If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground.
• If 1 V or greater
1. Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON.
2. Test for less than 1 V between the low reference circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K84 keyless entry control module.
• If less than 1 V
Note: When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 000.0 V.
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
9. Verify the MAX voltage captured by the DMM is greater than 1 V.
• If 1 V or less
1. Ignition OFF, disconnect the harness connector at the K84 keyless entry control module.
2. Test for infinite resistance between the low reference circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohm in the low reference circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K84 keyless entry control module.
• If greater than 1 V
10. Replace the T10K center console rear keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
12. Verify DTC B3123 is not set.
• If DTC B3123 is set
Replace the K84 keyless entry control module.
• If DTC B3123 is not set
13. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Ignition Lock Key Transmitter Antenna Replacement - Floor Console Ignition Lock Key Transmitter Antenna Replacement - Floor Console
* Control Module References Control Module References for keyless entry control module replacement, programming, and setup