For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC B1283: TV Antenna 1 Performance
DTC B1284: TV Antenna 2 Performance
DTC B1285: TV Antenna 3 Performance
DTC B1286: TV Antenna 4 Performance

### Circuit/System Description

The TV antenna signal return consists of 4 separate coax cables. These cables transmit the signal received from the TV antenna to the TV antenna amplifier, and enter the TV antenna module.

### Conditions for Running the DTC

This test is run every 300 milliseconds.

### Conditions for Setting the DTC

The TV antenna module detects that one or more of the 4 coax cables is open or shorted to ground for over 20 seconds.

### Action Taken When the DTC Sets

If the TV antenna module detected one or more of the coax cables are shorted to ground, all the 4 cable signal inputs would be shielded; If the TV antenna module detected one or more of the coax cables are open, other unaffected return circuits would continue the operation.

### Conditions for Clearing the DTC

The conditions for setting the DTC are not present.

The history DTC clears after 50 malfunction-free ignition cycles.

With the scan tool, use its Clear the DTC function to clear the DTC.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Entertainment/Communication Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

1. Turn off the TV function, disconnect the 4 TV antenna coax cables from the TV antenna amplifier.
2. Turn on the TV function and wait 20 seconds to ensure the voltage on the center conductor of 4 coax cables exceeds 1 volt.

⇒ | If the voltage on a certain cable connector is less than 1 volt, replace the suspect coax cable.

⇒ | If the voltage on the 4 cable connectors is less than 1 volt, refer to Component Test (Coax - TV Antenna Module to TV Antenna Amplifier).

3. Turn off the TV function and reconnect the coax cable to the TV antenna amplifier.
4. Disconnect the 4 TV antenna coax cables from the TV antenna.
5. Turn on the TV function and wait 20 seconds to ensure the voltage on the center conductor of 4 coax cables exceeds 1 volt.

⇒ | If the voltage on the 4 cable connectors is less than 1 volt, refer to Component Test (Coax - TV).

⇒ | If the voltages at the 4 cable connectors are all less than 1 volt, replace the rear windscreen (TV antenna).

⇒ | If the voltage on a certain cable connector is less than 1 volt, replace the suspect coax cable.

### Component Test (Coax Cables - TV Antenna Module to TV Antenna Amplifier)

Perform the Circuit/System Verification before proceeding with the diagnostic procedure.

1. Place the ignition switch in OFF position. Disconnect the 4 TV antenna coax cables from the TV antenna module and TV antenna amplifier, and measure the resistances of each cable center conductor from both ends, with the resistance of each less than 5 ohms.

⇒ | If the resistance is greater than 5 ohms, replace the suspect coax cable.

2. Measure the resistance of each coax outer metal drain wire from both ends, with the resistance of each less than 5 ohms.

⇒ | If the resistance is greater than 5 ohms, replace the suspect coax cable.

3. Measure the resistance between each coax center conductor and outer metal drain wire, and ensure the resistance between them is infinite, namely an open.

⇒ | If there is a resistance between them, replace the suspect coax. If the resistance of coax cable tests normal, replace the TV antenna module.

### Component Test (Coax Cables - TV Antenna Amplifier to TV Antenna)

Perform the Circuit/System Verification before proceeding with the diagnostic procedure.

1. Place the ignition switch in OFF position. Disconnect the 4 TV antenna coax cables from the TV antenna module and TV antenna amplifier.
2. Measure the resistance of each coax center conductor from both ends, with the resistance of each less than 5 ohms.

⇒ | If the resistance is greater than 5 ohms, replace the suspect coax cable.

3. Measure the resistance of each coax outer metal drain wire from both ends, with the resistance of each less than 5 ohms.

⇒ | If the resistance is greater than 5 ohms, replace the suspect coax cable.

4. Measure the resistance between each coax center conductor and outer metal drain wire, and ensure the resistance between them is infinite, namely an open.

⇒ | If there is a resistance between them, replace the suspect coax. If the resistance of coax cable tests normal, replace the TV antenna amplifier.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | TV Antenna Amplifier Replacement

• | Television Antenna Module Replacement.