Diesel Data: Automotive Repair

Symptom Troubleshooting




Audio System 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 Testing and Inspection.
- Check the connectors for poor connections or loose terminals.
- Check for aftermarket accessories including cell phones and chargers plugged into the vehicle accessory power sockets.
- 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.
- Aftermarket metallic window tint.
- A tall buildings, mountains, or a high-voltage power lines are nearby.

1. Turn the ignition switch to ON (II).

2. Do the Seek Stop Test and the reception level indication in the self-diagnostic function.

Is the test vehicle within 10 % of the known-good vehicle?

YES -

Multipath interference or weak station. Operation is normal.�

NO -

Go to step 3.

3. Check that the radio reception/interference is the same in several different 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. Check the reception/interference while the engine is running.

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

YES -

Check the antenna and radio grounds. If OK, check the charging system and the ignition system.�

NO -

Go to step 5.

5. Turn the ignition switch to LOCK (0).

6. Remove the rear roof trim Rear Roof Trim Replacement.

7. Wrap aluminum foil (A) around the tip of a tester probe (B) as shown.






8. Touch one tester probe to the antenna element 1P connector No. 1 terminal, and the other tester probe at the antenna element to check for continuity. Replace if there is no continuity.





9. Remove the audio unit Audio Unit Removal/Installation. Check that the AM/FM antenna sub-lead and main-lead are properly connected.

Are they connected properly?

YES -

Go to step 10.

NO -

Reconnect the connector, and recheck the function.�

10. Turn the ignition switch to ON (II).

11. Turn on the audio unit, and select AM or FM.

12. Measure the voltage between AM/FM antenna amplifier 3P connector terminal No. 3 and body ground.





Is there battery voltage?

YES -

Go to step 18.

NO -

Go to step 13.

13. Tune the ignition switch to LOCK (0).

14. Remove the audio unit Audio Unit Removal/Installation.

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

15. Disconnect audio unit connector D (3P).

16. Check for continuity between audio unit connector D (3P) terminal No. 3 and the AM/FM antenna amplifier 3P connector terminal No. 3.





Is there continuity?

YES -

Go to step 17.

NO -

Repair an open in the wire between the audio unit and the AM/FM antenna amplifier. Also check the AM/FM antenna lead and/or sublead connections.�

17. Check for continuity between audio unit connector D (3P) terminal No. 3 and body ground.





Is there continuity?

YES -

Repair a short to ground in the wire between the audio unit and the AM/FM antenna.�

NO -

Substitute a known good audio unit Audio Unit Removal/Installation, and recheck.�

18. Turn the ignition switch to LOCK (0).

19. Remove the audio unit Audio Unit Removal/Installation.

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

20. Disconnect audio unit connector D (3P).

21. Check for continuity between audio unit connector D (3P) terminal No. 1 and AM/FM antenna amplifier 3P connector terminal No. 1.





Is there continuity?

YES -

Go to step 22.

NO -

Replace the AM/FM antenna lead and/or the sublead.�

22. Check for continuity between audio unit connector D (3P) terminal No. 1 and body ground.





Is there continuity?

YES -

Replace the AM/FM antenna lead and/or the sublead.�

NO -

Go to step 23.

23. Check for continuity between audio unit connector D (3P) terminal No. 2 and AM/FM antenna amplifier 3P connector terminal No. 2.





Is there continuity?

YES -

Go to step 24.

NO -

Replace the AM/FM antenna lead and/or the sublead.�

24. Check for continuity between audio unit connector D (3P) terminals No. 1 and No. 2.





Is there continuity?

YES -

Replace the AM/FM antenna lead and/or the sublead.�

NO -

Replace the AM/FM antenna amplifier Service and Repair, and recheck. If the reception is still poor, substitute a known-good audio unit Audio Unit Removal/Installation, and recheck. If the symptom/indication goes away, replace the audio unit Audio Unit Removal/Installation.�