Poor AM/FM Radio Reception or Interference

Poor AM or FM radio reception or interference

NOTE:
- Check the vehicle battery condition first.
- Check for after market accessories.
- Check the connectors for poor connections or loose terminals.
- Check the radio reception in an open area. Poor reception/interference can be caused by the following:
- The radio station is far away.
- Atmospheric conditions are unfavorable.
- Tall buildings, mountains, or high-voltage power lines are nearby.

1. Turn the ignition switch to ON (II).
2. Do the seek stop test.

Is the number of stations the same or within 10 % of the known-good vehicle?

YES - Multipath interference or weak station. Operation is normal.

NO - Go to step 3.

3. Check if the radio reception/interference is the same in several locations.

Is the reception/interference the same?

YES - Go to step 4.

NO - Multipath interference or weak station. Operation is normal.

4. Start the engine.
5. Check the reception/interference while the engine is running.

Is there noise (static or whine) only with the engine running?

YES - Check all of the AM/FM antenna connections and the AM/FM antenna and radio grounds. If OK, check the charging system and the ignition system.

NO - Go to step 6.

6. Turn the ignition switch to LOCK (0).
7. Check the antenna mast for cracks, or other damage. Make sure that the AM/FM antenna mast isn't loose.

NOTE: Do not use any tools to tighten the antenna mast.

Is there any damage?

YES - Replace the AM/FM antenna mast.

NO - Go to step 8.

8. Turn the ignition switch to ON (II).
9. Turn on the audio unit.
10. Measure the voltage between AM/FM antenna 2P connector terminal No. 2 and body ground.






Is there battery voltage?

YES - Go to step 11.

NO - Go to step 18.

11. Turn the ignition switch to LOCK (0).
12. Remove the audio unit, and disconnect the AM/FM antenna lead.
13. Disconnect the AM/FM antenna lead from the AM/FM antenna.
14. Check for continuity between the AM/FM antenna lead center pin at the audio unit side and body ground.






Is there continuity?

YES - Replace the AM/FM antenna lead.

NO - Go to step 15.

15. Check for continuity between the AM/FM antenna lead center pin and the surface of the AM/FM antenna lead.






Is there continuity?

YES - Replace the AM/FM antenna lead.

NO - Go to step 16.

16. Check for continuity between the AM/FM antenna lead center pin at the audio unit side and the AM/FM antenna lead center pin at the AM/FM antenna side.






Is there continuity?

YES - Go to step 17.

NO - Replace the AM/FM antenna lead.

17. Substitute a known-good AM/FM antenna lead, and check the radio reception.

Is the reception normal?

YES - Replace the AM/FM antenna lead.

NO - Substitute a known-good audio unit and recheck. If the reception is still poor, replace the AM/FM antenna.

18. Turn the ignition switch to LOCK (0).
19. Remove the audio unit and disconnect the audio unit 20P connector.

NOTE: Eject the disc before removing the audio unit to prevent damaging the CD player's load mechanism.

20. Check for continuity between audio unit 20P connector terminal No. 1 and AM/FM antenna 2P connector terminal No. 2.






Is there continuity?

YES - Substitute a known-good audio unit and retest.

NO - Repair open in the wire between the audio unit and the AM/FM antenna.