For 1990-2009 cars

### Circuit Description

The antenna enable/amplifier on signal is a class 2 signal sent from the radio through the rear seat audio (RSA) module, when equipped. The amplifier will reach full output capabilities 900 milliseconds after receiving this signal. The amplifier will then be capable of class 2 functions 60 milliseconds after being turned ON. This DTC will be set if the circuit is shorted to ground or battery.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1235 Amplifier On Signal Circuit

### Conditions for Running the DTC

This test is run at least every 50 milliseconds.

### Conditions for Setting the DTC

The failure must occur for at least 3 seconds.

### Action taken when the DTC Sets

The antenna enable/amplifier on signal circuit becomes disabled, causing the controlled module to become inoperative.

### Conditions for Clearing the DTC

The failure criteria is no longer detected for 50 milliseconds.

### Test Description

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

1. This step helps to determine if the Diversity Antenna System is operating.

1. This step helps to determine if radio antenna module is receiving the proper signal from the radio.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Radio/Navigation System Schematics
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn ON the ignition, with the engine OFF.
2. Turn ON the radio.
3. Press the scan button.

Do the local AM/FM stations come in clearly?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3 |

1. Remove the radio.
2. Test the antenna enable/amplifier on signal circuit for a short or open.

Did you locate and correct the condition?

Go to Step 4

Go to Testing for Intermittent Conditions and Poor Connections

4 | Operate the system in order to verify the repair. Did you complete the repair? | System OK | --