07 - Inspection Procedure

Broadcasts can be Heard but Both AM and FM have a Lot of Noise

DIAGNOSIS

STEP 1. Check that the noise occur when the engine is stopped or the engine is running.

Q: Does noise occur when the engine is stopped or the engine is running?
When the engine is stopped : Go to Step 2.
When the engine is running : Check the vehicle's noise suppressor. (Refer to Inspection Procedure 12.)

STEP 2. Check that the following actions disappear the noise.

1. Tune to a station with a stronger wave.
2. Extend the antenna completely (Mast antenna).
3. Adjust the sound quality to suppress high tones.

Q: Is the noise eliminated?

YES: Consult the radio manufacturer's service center.

NO: Go to Step 3.

STEP 3. Check that the radio is correctly grounded

Q: Is the radio correctly grounded?

YES: Go to Step 4.

NO: Consult the radio manufacturer's service center.

STEP 4. Check that the antenna plug properly connected to the radio?

Q: Is the antenna plug properly connected to the radio?

YES: Go to Step 7.

NO: Go to Step 5.

STEP 5. Check that the noise is eliminated when the antenna plug is properly attached.

Q: Is the noise eliminated?

YES: Consult the radio manufacturer's service center.

NO: Go to Step 6.

STEP 6. Check that the antenna is in good condition and is it properly mounted.

Q: Is the antenna in good condition and is it properly mounted?

YES: Consult the radio manufacturer's service center.

NO: Go to Step 7.

STEP 7. Clean the antenna plug and ground wire mounting area. Mount the antenna securely.

NOTE: Noise encountered during FM reception only due to differences in FM and AM system, FM is not as susceptible as AM to interference from engines, power lines, lighting, etc. On the other hand, due to the characteristics of FM waves, there are sometimes cases of noise or distortion which are generated by typical noise interference (first fading and multipath). (Refer to Inspection Procedure 5.) in weak signal areas such as mountainous regions, but this is not due to a problem with the radio.>

NOTE: Furthermore, the amount of interference will be comparatively less for vehicles equipped with a diversity antenna system*. If there is an equivalent amount of distortion in vehicles or radios of the same type, then differences will be because of differences in antenna systems, and this should be explained to the user.

NOTE: Diversity antenna system*: A system where two types of antenna (glass main antenna and glass sub antenna) are equipped and the antenna that provides the best reception car be selected.

Q: Is the antenna in good condition?

YES: Consult the radio manufacturer's service center.

NO: Clean or repair it. Check the noise is eliminated. If the noise is not eliminated, consult the radio manufacturer's service center.