Audio System Symptom Troubleshooting - Poor AM or FM radio reception or interference
Poor AM or FM radio reception or interference
NOTE:
Check the vehicle 12 volt battery condition first.
Check for aftermarket accessories plugged into the vehicle accessory power sockets.
Check for any radio frequency modulators that are plugged into the FM antenna lead. These modulators allow customers to play audio from accessories like CD players or game consoles using the audio system, but they can create interference issues.
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
?
Electrical loads like the rear window defroster, seat heaters, game consoles, etc.
Check the connectors for poor connections or loose terminals.
1.
Problem verification:

Problem verification
?1.
Park the vehicle in an open area.

?2.
Turn the vehicle to the ON mode.

?3.
Turn on the audio system, and select AM or FM radio station.

Is the sound quality normal?

     
YES
     
     
     
Intermittent failure, the system is OK at this time.?
     
NO
     
     
     
The failure is duplicated, go to step 2.
2.
Reception/interference check:

Reception/interference check
?1.
Check if the radio reception/interference is the same as the known-good vehicle in several locations.

Is the AM or FM sound quality the same?

     
YES
     
     
     
Multipath interference or weak station. Operation is normal.?
     
NO
     
     
     
Go to step 3.
3.
Determine possible failure area (ANT ?B line, others):

Determine possible failure area (ANT ?B line, others)
?1.
Disconnect the following connector.
Roof antenna connector A (3P)

?2.
Turn the vehicle to the ON mode.

?3.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
 
Roof antenna connector A (3P): disconnected
Test point 1
Roof antenna connector A (3P) (male terminals) No. 1:
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The ANT ?B wire is OK. Go to step 6.
     
NO
     
     
     
Go to step 4.
4.
Shorted wire check (ANT ?B line):

Shorted wire check (ANT ?B line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Audio unit connector E (3P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna connector A (3P): disconnected
 
Audio unit connector E (3P): disconnected
Test point 1
Roof antenna connector A (3P) (male terminals) No. 1:
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire.?
     
NO
     
     
     
The ANT ?B wire is not shorted to ground. Go to step 5.
5.
Open wire check (ANT ?B line):

Open wire check (ANT ?B line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna connector A (3P): disconnected
 
Audio unit connector E (3P): disconnected
Test point 1
Audio unit connector E (3P) No. 1
Test point 2
Roof antenna connector A (3P) (male terminals) No. 1:


Is there continuity?

     
YES
     
     
     
     
NO
     
     
     
Repair an open in the wire.?
6.
Shorted wire check (RF IN line):

Shorted wire check (RF IN line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Audio unit connector E (3P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna connector A (3P): disconnected
 
Audio unit connector E (3P): disconnected
Test point 1
Roof antenna connector A (3P) (male terminals) No. 2:
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
There is a short to body ground in the wire. Replace the affected antenna lead.?
     
NO
     
     
     
The RF IN wire is not shorted to ground. Go to step 7.
7.
Shorted wire check (RF IN line to SH (RF IN) line):

Shorted wire check (RF IN line to SH (RF IN) line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna connector A (3P): disconnected
 
Audio unit connector E (3P): disconnected
Test point 1
Audio unit connector E (3P) No. 2
Test point 2
Audio unit connector E (3P) No. 3

Is there continuity?

     
YES
     
     
     
There is a short in the wire. Replace the affected antenna lead.?
     
NO
     
     
     
The RF IN wire is not shorted to SH(RF IN) wire. Go to step 8.
8.
Open wire check (RF IN line):

Open wire check (RF IN line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna connector A (3P): disconnected
 
Audio unit connector E (3P): disconnected
Test point 1
Roof antenna connector A (3P) (male terminals) No. 2:
Test point 2
Audio unit connector E (3P) No. 2


Is there continuity?

     
YES
     
     
     
The RF IN wire is OK. Go to step 9.
     
NO
     
     
     
There is an open in the wire. Replace the affected antenna lead.?
9.
Roof antenna check (substitution):

Roof antenna check (substitution)
?1.
Substitute a known-good roof antenna.

?2.
Reconnect all the connectors, and recheck.

Does the symptom go away?

     
YES
     
     
     
     
NO