Pinpoint Test A: Poor Reception

Normal Operation 

Audio waves are received by the antenna grid (located in the rear glass) and transferred to the audio unit through the antenna cable. The radio suppression equipment reduces interference caused by the electrical components of the ignition and charging systems. When the SEEK/SCAN button is pressed, the audio unit searches for a channel with sufficient audio signal strength and automatically stops when it reaches one.

• DTC B2103 (Antenna Not Connected) - sets when the antenna signal is lower than the pre-configured threshold value during the audio unit self-test.

This pinpoint test is intended to diagnose the following:

• Antenna
• Antenna cable
• Noise suppression equipment
• Charging system
• Ignition system
• Audio unit

PINPOINT TEST A: POOR RECEPTION 

1. A1 CHECK THE RADIO SIGNAL RECEPTION 
   • Check the audio unit signal reception with the engine running and with the engine off.
   • Is the audio unit signal reception noisy/missing only with the engine running? 
   1. YES  : Go to  A2.
   2. NO  : Go to  A8.
2. A2 CHECK THE SUPPRESSION EQUIPMENT 
   • Check all required suppression equipment, radio frequency interference suppression bond, and the hood bonding strap for security, cleanliness, and metal-to-metal contact.
   • Check the bolts holding the antenna module and ground to the rear shelf for security, cleanliness, and metal-to-metal contact.
   • Are the contacts clean, secure, and in metal-to-metal contact? 
   1. YES  : Go to  A3.
   2. NO  : CLEAN or SECURE the connections as necessary. TEST the system for normal operation.
3. A3 CHECK THE CAPACITOR MOUNTING AND CONNECTING CIRCUITS 
   NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.
   • Check the mounting and connecting circuits of the radio ignition interference capacitor(s) for security, cleanliness, and metal-to-metal contact.
   • Are the contacts clean, secure, and in metal-to-metal contact? 
   1. YES  : Go to  A4.
   2. NO  : CLEAN or SECURE the connections as necessary. TEST the system for normal operation.
4. A4 CHECK THE RADIO IGNITION INTERFERENCE CAPACITOR(S) AND THE GENERATOR 
   • Key in OFF position.
   • Check the operation of the radio ignition interference capacitor(s) or suppression equipment by installing a known good component(s).
   • Check the generator by disconnecting the wiring harness from the voltage regulator.
   • Start the vehicle.
   • Check the operation of the audio unit.
   • Is the reception OK? 
   1. YES  : REPAIR or INSTALL new components as necessary. TEST the system for normal operation.
   2. NO  : Go to  A5.
5. A5 CHECK THE IGNITION CIRCUITS 
   • Key in OFF position.
   • Check the ignition circuits for correct routing, grounding, and security of the connections.
   • Are the circuits OK? 
   1. YES  : Go to  A6.
   2. NO  : REPAIR the circuits as necessary. TEST the system for normal operation.
6. A6 CHECK THE IGNITION SYSTEM 
   • Test the ignition system. Refer to the Introduction - Gasoline Engines article.
   • Is the ignition system OK? 
   1. YES  : Go to  A7.
   2. NO  : REPAIR the ignition system. REFER to ENGINE IGNITION - 4.6L (2V) article. TEST the system for normal operation.
7. A7 SUBSTITUTE THE AUDIO UNIT 
   • Key in OFF position.
   • Substitute a known good audio unit.
   • Start the vehicle.
   • Check the operation of the audio unit.
   • Is the reception OK? 
   1. YES  : INSTALL a new audio unit. REFER to Audio Unit . TEST the system for normal operation.
   2. NO  : INSTALL the original audio unit. USE a jumper cable to ground various parts of the vehicle to the frame (for example: engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal). When the noise is eliminated, PROVIDE a permanent ground where necessary. TEST the system for normal operation.
8. A8 CHECK THE ON-GLASS ANTENNA FOR DAMAGE 
   • Key in OFF position.
   • Disconnect: Antenna Lead Terminal
   • Measure the resistance between the antenna cable lead terminal and the end of the antenna grid wire.
   • Is the resistance less than 8 ohms? 
   1. YES  : Go to  A9.
   2. NO  : REPAIR the grid lines as necessary. REFER to GLA↓SS, FRAMES & MECHANISMS article. CLEAR the DTCs. REPEAT the self-test.
9. A9 SUBSTITUTE THE ANTENNA EXTENSION CABLE(S) 
   • Key in OFF position.
   • Substitute a known good antenna cable between the antenna grid and the audio unit.
   • Key in ON position.
   • Check the operation of the audio unit.
   • Is the reception OK? 
   1. YES  : INSTALL a new antenna cable. CLEAR the DTCs. REPEAT the self-test.
   2. NO  : INSTALL the original antenna cable. INSTALL a new audio unit. REFER to Audio Unit . TEST the system for normal operation after the repair.