For 1990-2009 cars

### Circuit Description

The console active antenna is located in the center console and is used as a short range low frequency (LF) antenna. The keyless entry console active antenna is only used when a keyless entry transmitter battery is low or there is an interruption with the frequency transmission of the passive antennas located in the console and headliner. When a valid transmitter is placed into the fob pocket, the brake pedal is depressed, and the ignition button is pressed, the console active antenna broadcasts a challenge to the transmitter. This causes a low frequency coupling to occur between the transmitter and the console active antenna. If the response from the transmitter is a valid response, and all of the security requirements are met, the vehicle's engine will start, or be allowed to go into accessory mode.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3122 Keyless Entry Antenna 4 Performance

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
04 | Open Circuit

### Conditions for Setting the DTC

The remote control door lock receiver (RCDLR) will set this DTC during antenna activation if the circuits involved with the console active antenna's operation is open, shorted to battery, or shorted to ground. The RCDLR can only set a DTC when the vehicle system voltage is between 9-16 volts.

### Action Taken When the DTC Sets

The RCDLR will set and store a DTC B3122.

### Conditions for Clearing the DTC

• | The RCDLR no longer detects an open, a short to power, or a short to ground.

• | Use the scan tool.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step verifies that proper operation of the keyless entry console active antenna

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Remote Function Schematics Connector End View Reference: Remote Function Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install the scan tool.
2. Place the keyless entry transmitter in the fob pocket located within the center console.
3. In the RCDLR output controls menu, select Active Antenna
4. Attempt to authenticate the Active Antenna

Does the Active Antenna authenticate?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3 | At the RCDLR, measure the voltage of the Keyless Entry Active Antenna Supply Voltage circuit with a DMM. Does the voltage equal the specified value? | 0V | Go to Step 4 | Go to Step 7
4 | At the RCDLR, measure the voltage of the Keyless Entry Active Antenna Data Signal circuit with a DMM. Does the voltage equal the specified value? | 0V | Go to Step 5 | Go to Step 8
5 | At the RCDLR, measure the voltage of the Keyless Entry Active Antenna Clock Signal circuit with a DMM. Does the voltage equal the specified value? | 0V | Go to Step 9 | Go to Step 6
6 |

1. At the RCDLR, measure the voltage of the Keyless Entry Active Antenna Low Reference circuit with a DMM.
2. With the scan tool, go to the Active Antenna output control in the RCDLR special functions menu.
3. While viewing the DMM, attempt to authenticate the Active Antenna.

Does the voltage transition to the specified value?

OL

Go to Step 11

Go to Step 10

7 | Test the Keyless Entry Active Antenna Supply Voltage circuit for one of the following:

• | Short to ground

• | Short to power

• | Open

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

8 | Test the Keyless Entry Active Antenna Data Signal circuit for one of the following:

• | Short to ground

• | Short to power

• | Open

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

9 | Test the Keyless Entry Active Antenna Clock Signal circuit for one of the following:

• | Short to ground

• | Short to power

• | Open

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

10 | Test the Keyless Entry Active Antenna Low Reference circuit for one of the following:

• | Short to ground

• | Short to power

• | Open

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

11 | Inspect for poor connections at the RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13
12 | Inspect for poor connections at the Keyless Entry Active Antenna. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14
13 | Replace the RCDLR. Refer to Control Module References for replacement, setup, and programming. Is the replacement complete? | -- | Go to Step 15 | --
14 | Replace the Keyless Entry Active Antenna. Refer to Ignition Lock Key Transmitter Antenna Replacement - Headliner . Is the replacement complete? | -- | Go to Step 15 | --
15 |

1. Clear the DTCs with the scan tool.
2. Operate the vehicle under conditions when DTC runs as specified in supporting documents.

Does the DTC set again?

--

System OK

Go to Step 2