Symptom Troubleshooting

Symptom Troubleshooting: Poor AM or FM radio reception or interference

Poor AM or FM radio reception or interference

NOTE:

- Check the vehicle battery condition first.

- Check for aftermarket 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. Sound Quality Diagnosis - 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 as a known-good vehicle in several different locations?
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. Service and Repair

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, Service and Repair 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, Service and Repair and recheck. If the reception is still poor, replace the AM/FM antenna. Service and Repair


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, Service and Repair and retest.

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