Poor AM/FM Radio Reception Or Interference

WARNING: This page is about a different car, the 2006 Acura MDX, 2005 Acura MDX, 2004 Acura MDX, and 2003 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Check the AM/FM radio reception in an open area. Poor reception/interference can be caused by the following:

The radio station is too far away.
A tall building, a mountain, or high-voltage power line is nearby.
Aftermarket window tinting.

Check if each AM/FM radio station can be received normally. Compare the radio reception/interference to another vehicle of the same model and trim level in the exact same conditions.
Are they the same?
1. YES - Operation is normal.
2. NO - Go to step 2.
Check if the AM/FM radio reception/interference is the same in several locations.
Is the reception/interference the same?
1. YES - Go to step 3.
2. NO - Multipath interference or weak station. Operation is normal.
Check the reception/interference while the engine is running.
Is there noise (static or whine) only with the engine running?
1. YES - Check the antenna and radio grounds. If OK, check the charging system and the ignition system.
2. NO -
  - With XM radio: go to step 4.
  - Without XM radio: go to step 15.
Wrap aluminum foil (A) around the tip of a tester probe (B) as shown in Fig 1.

Fig 1: Wrapping Aluminum Foil Around Tip Of A Tester Probe
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Touch one tester probe to the window antenna terminal (A) here, and move the other tester probe along the antenna wires to check that continuity exists. Repair it continuity does not exist.

Fig 2: Touching One Tester Probe To Window Antenna Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the audio unit (see AUDIO UNIT REMOVAL/INSTALLATION ). Check that antenna lead is properly connected.
Is it connected properly?
1. YES - Go to step 7.
2. NO - Reconnect the connector, and recheck the function.
Disconnect the antenna amplifier connector from the antenna amplifier.
Measure voltage between the antenna amplifier connector No. 3 terminal and body ground.

Fig 3: Measuring Voltage Between Antenna Amplifier Connector No. 3 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 9.
2. NO - Faulty antenna lead.
Remove the audio unit (see AUDIO UNIT REMOVAL/INSTALLATION ).
Check for continuity between the audio unit antenna cable 3P connector No. 3 terminal and the antenna module 3P connector No. 3 terminal.

Fig 4: Checking Continuity Between Audio Unit Antenna Cable 3P Connector 3 Terminal And Antenna Module 3P Connector 3 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 11.
2. NO - Repair the open in the wire between the audio unit and the antenna module.
Check for continuity between the audio unit antenna cable 3P connector No. 1 terminal and the antenna module 3P connector No. 1 terminal.

Fig 5: Checking Continuity Between Audio Unit Antenna Cable 3P Connector 1 Terminal And Antenna Module 3P Connector 1 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 12.
2. NO - Replace the antenna lead.
Check for continuity between the audio unit antenna cable 3P connector No. 1 terminal and body ground.

Fig 6: Checking Continuity Between Audio Unit Antenna Cable 3P Connector 1 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Replace the antenna lead.
2. NO - Go to step 13.
Check for continuity between the audio unit antenna cable 3P connector No. 2 terminal and the antenna module 3P connector No. 2 terminal.

Fig 7: Checking Continuity Between Audio Unit Antenna Cable 3P Connector 2 Terminal And Antenna Module 3P Connector 2 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Replace the antenna lead.
2. NO - Go to step 14.
Check for continuity between the audio unit antenna cable 3P connector No. 1 and No. 2 terminals.

Fig 8: Checking Continuity Between Audio Unit Antenna Cable 3P Connector 1 And 2 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Replace the antenna lead.
2. NO - Replace the antenna module, and recheck. If the reception is still poor, replace the audio unit.
Remove the audio unit (see AUDIO UNIT REMOVAL/INSTALLATION ).
Disconnect the antenna leads from the audio unit and mast antenna.
Check for continuity between the antenna lead center pin at the audio unit lead and the antenna lead center pin at the antenna module unit lead.

Fig 9: Checking Continuity Between Antenna Lead Center Pin At Audio Unit Lead And At Antenna Module Unit Lead
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 18.
2. NO - Replace the antenna lead.
Check for continuity between the shield surface of the audio unit lead and the shield surface of the antenna module unit lead.

Fig 10: Checking Continuity Between Shield Surface Of Audio Unit Lead And Antenna Module Unit Lead
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 19.
2. NO - Replace the antenna lead.
Check for continuity between the antenna lead center pin and the surface of the antenna lead.

Fig 11: Checking Continuity Between Antenna Lead Center Pin And Surface Of Antenna Lead
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Replace the antenna lead.
2. NO - Go to step 20.
Disconnect the audio unit connector A (20P).
Check for continuity between audio unit connector A (20P) terminal No. 1 and antenna amplifier connector No. 1 terminal.

Fig 12: Checking Continuity Between Audio Unit Connector A (20P) Terminal 1 And Antenna Amplifier Connector 1 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Substitute a known-good audio unit and retest.
2. NO - Repair the open in the wire between the audio unit and the antenna module.