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

   -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

   -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)

   -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

   Courtesy of HONDA, U.S.A., INC.

   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)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   Audio unit connector E (3P)

   -3. Measure the resistance 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

   Courtesy of HONDA, U.S.A., INC.

   Is there 1.0 MΩ or more?

   YES 

   The ANT +B wire is not shorted to ground. Go to step 5.

   NO 

   Repair a short to body ground in the wire.

5. Open wire check (ANT +B line)

   -1. Measure the resistance 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:

   Courtesy of HONDA, U.S.A., INC.

   Is there 1.0 Ω or less?

   YES 

   Replace the audio unit .

   NO 

   Repair an open in the wire.

6. 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. Measure the resistance 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

   Courtesy of HONDA, U.S.A., INC.

   Is there 1.0 MΩ or more?

   YES 

   The RF IN wire is not shorted to ground. Go to step 7.

   NO 

   There is a short to body ground in the wire. Replace the affected antenna lead.

7. Shorted wire check (RF IN line to SH (RF IN) line)

   -1. Measure the resistance 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 1.0 MΩ or more?

   YES 

   The RF IN wire is not shorted to SH (RF IN) wire. Go to step 8.

   NO 

   There is a short in the wire. Replace the affected antenna lead.

8. Open wire check (RF IN line)

   -1. Measure the resistance 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

   Courtesy of HONDA, U.S.A., INC.

   Is there 1.0 Ω or less?

   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)

   -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 

   Replace the audio unit .