Poor AM or FM Radio Reception or Interference (Without Navigation)

Poor AM or FM Radio Reception Or Interference (Without Navigation)

NOTE:
- Check the radio reception in an open area.
- Compare it to a known-good vehicle of the same model, year, and trim level whenever possible.
- If necessary, have the customer demonstrate the symptom.
- Poor reception/interference can be caused by any of these conditions.
- The radio station is far away.
- Atmospheric conditions are unfavorable.
- A tall buildings, mountains, or high-voltage power lines are nearby.
- Aftermarket window tinting or electronic accessories.
- Non-standard antenna mast.
- Check the vehicle battery condition first.
- Check the connectors for poor connections or loose terminals.

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

Does the test vehicle receive 90 % of the same stations as the known-good vehicle?

YES - Multipath interference or weak station. Operation is normal at this time.

NO - Go to step 3.

3. Check if the radio reception/interference is the same as the known-good vehicle in several locations.

Is the reception/interference the same?

YES - Go to step 4.

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

4. Check the reception/interference while the engine is running and compare it to the known-good vehicle.

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

YES - Check the antenna and radio grounds. If OK, check the charging system, fuel injection system (fuel pump), HVAC (blower motor), and the ignition system.

NO - Go to step 5.

5. Turn the ignition switch to LOCK (0).
6. Check the antenna mast for cracks, or other damage. Make sure that the AM/FM/XM antenna is not loose.

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

Is there any damage?

YES - Replace the AM/FM/XM antenna.

NO - Go to step 7.

7. Disconnect the antenna cable 3P connector from the AM/FM/XM antenna.
8. Turn the ignition switch to ON (II).
9. Measure the voltage between the antenna cable connector No. 3 terminal at the antenna amplifier lead and body ground.






Is there battery voltage?

YES - Go to step 15.

NO - Go to step 10.

10. Turn the ignition switch to LOCK (0).
11. Remove the audio unit.
12. Disconnect audio unit connector G (3P).
13. Check for continuity between audio unit connector G (3P) No. 3 terminal and the antenna amplifier 3P connector No. 3 terminal.






Is there continuity?

YES - Go to step 14.

NO - Repair open in the wire between the audio unit and the antenna amplifier.

14. Check for continuity between the antenna amplifier connector (3P) No. 3 terminal and body ground.






Is there continuity?

YES - Repair short in the wire between the audio unit and the antenna amplifier.

NO - Substitute a known-good audio unit, and recheck.

15. Remove the audio unit.
16. Check for continuity between audio unit connector G (3P) No. 1 terminal and the antenna amplifier 3P connector No. 1 terminal.






Is there continuity?

YES - Go to step 17.

NO - Replace the antenna lead and/or sublead.

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






Is there continuity?

YES - Replace the antenna lead and/or sublead.

NO - Go to step 18.

18. Check for continuity between audio unit connector G (3P) No. 2 terminal and the antenna amplifier 3P connector No. 2 terminal.






Is there continuity?

YES - Replace the antenna lead and/or sublead.

NO - Go to step 19.

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






Is there continuity?

YES - Replace the antenna lead and/or sublead.

NO - Replace the antenna amplifier, and recheck. If the reception is still poor, replace the audio unit.