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 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 metallic window tinting or electronic accessories
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.
Seek stop test:

Seek stop test
?1.
Do the Seek Stop Test in the Sound Quality Diagnosis.

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

     
YES
     
     
     
Multipath interference or weak station. Operation is normal.?
     
NO
     
     
     
The failure is duplicated, go to step 3.
3.
Determine possible failure area (charging system and ignition system, others):

Determine possible failure area (charging system and ignition system, others)
?1.
Start the engine.

?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.?
     
NO: With front installation type roof antenna
     
     
     
Go to step 4.
     
NO: With rear installation type roof antenna
     
     
     
Go to step 7.
4.
Shorted wire check (AM/FM line):

Shorted wire check (AM/FM 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
 
Audio unit connector E (3P): disconnected
Test point 1
Audio unit connector E (3P) No. 2
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Replace the antenna main lead and/or the sublead.?
     
NO
     
     
     
The AM/FM wire is not shorted to ground. Go to step 5.
5.
Shorted wire check (AM/FM line to SH (AM/FM) line):

Shorted wire check (AM/FM line to SH (AM/FM) line)
?1.
Remove the roof antenna.

?2.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna: removed
 
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
     
     
     
Replace the antenna main lead and/or the sublead.?
     
NO
     
     
     
The AM/FM wire is not shorted to the SH (AM/FM) wire. Go to step 6.
6.
Open wire check (AM/FM line):

Open wire check (AM/FM line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Roof antenna: removed
 
Audio unit connector E (3P): disconnected
Test point 1
Audio unit connector E (3P) No. 2
Test point 2
Roof antenna mounting nut (A)


Is there continuity?

     
YES
     
     
     
The AM/FM wire is OK. Go to step 12.
     
NO
     
     
     
Replace the antenna main lead and/or the sublead.?
7.
Determine possible failure area (SWD +B line, AM/FM line):

Determine possible failure area (SWD +B line, AM/FM line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Roof antenna connector A (3P)

?3.
Turn the vehicle to the ON mode, and turn on the audio system.

?4.
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) No. 1
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The SWD +B wire is OK. Go to step 8.
     
NO
     
     
     
Go to step 13.
8.
Shorted wire check (AM/FM line):

Shorted wire check (AM/FM 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
Audio unit connector E (3P) No. 2
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Replace the antenna main lead and/or the sublead.?
     
NO
     
     
     
The AM/FM wire is not shorted to ground. Go to step 9.
9.
Shorted wire check (AM/FM line to SH (AM/FM) line):

Shorted wire check (AM/FM line to SH (AM/FM) 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
     
     
     
Replace the antenna main lead and/or the sublead.?
     
NO
     
     
     
The AM/FM wire is not shorted to the SH (AM/FM) wire. Go to step 10.
10.
Open wire check (AM/FM line):

Open wire check (AM/FM 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
Roof antenna connector A (3P) No. 2


Is there continuity?

     
YES
     
     
     
The AM/FM wire is OK. Go to step 11.
     
NO
     
     
     
Replace the antenna main lead and/or the sublead.?
11.
Open wire check (SH (AM/FM) line):

Open wire check (SH (AM/FM) 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. 3
Test point 2
Roof antenna connector A (3P) No. 3


Is there continuity?

     
YES
     
     
     
The SH (AM/FM) wire is OK. Go to step 12.
     
NO
     
     
     
Replace the antenna main lead and/or the sublead.?
12.
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
     
     
     
Replace the original roof antenna.?
     
NO
     
     
     
13.
Shorted wire check (SWD +B line):

Shorted wire check (SWD +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) No. 1
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the audio unit and the roof antenna.?
     
NO
     
     
     
The SWD +B wire is not shorted to ground. Go to step 14.
14.
Open wire check (SWD +B line):

Open wire check (SWD +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) No. 1


Is there continuity?

     
YES
     
     
     
     
NO
     
     
     
Repair an open in the wire between the audio unit and the roof antenna.?