Audio System Symptom Troubleshooting - Poor AM or FM radio reception or interference (Except 1DIN 1CD type)

Poor AM or FM radio reception or interference (Except 1DIN 1CD type)


NOTE: Check the radio reception in an open area. Compare it to a known-good vehicle whenever possible. 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.
  • Aftermarket window tinting or electronic accesories.

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

Is the reception/interference the same?


YES - Go to 2.


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


2.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.n


NO - Go to 3.

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

 

4.Touch one tester probe to the rear window antenna terminal (A) here, and move the other tester probe along the antenna wires to check that continuity exists. Repair if continuity does not exist.

 

5.Remove the audio unit. Check that the antenna lead is properly connected.

Is it connected properly?


YES - Go to 6.


NO - Reconnect the connector, and recheck the function.n

6.Disconnect the antenna cable 3P connector from the antenna module.

7.Measure the voltage between the antenna cable connector No. 3 terminal at the antenna module lead and body ground.

 

Is there battery voltage?


YES - Go to 8.


NO - Go to 12.


8.Check for continuity between audio unit connector C (3P) No. 1 terminal and the antenna module 3P connector No.1 terminal.

 

Is there continuity?


YES - Go to 9.


NO - Replace the antenna lead.n

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

 

Is there continuity?


YES - Replace the antenna lead.n


NO - Go to 10.


10.Check for continuity between audio unit connector C (3P) No. 2 terminal and the antenna module 3P connector No. 2 terminal.

 

Is there continuity?


YES - Replace the antenna lead.n


NO - Go to 11.

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

 

Is there continuity?


YES - Replace the antenna lead.n


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


12.Remove the audio unit.

13.Check for continuity between audio unit connector C (3P) No. 3 terminal and the antenna module 3P connector No. 3 terminal.

 

Is there continuity?


YES - Go to 14.


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

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

 

Is there continuity?


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


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