Inspection Procedure 15

INSPECTION PROCEDURE 15: Noise is Present While Moving (FM)

DIAGNOSIS

STEP 1 Check the radio after adjusting it

Q: Readjust the radio Is the noise eliminated?

YES: Check that there is no noise

NO: Go to Step 2

STEP 2 Check with several broad casting

NOTE: Multipath noise and fading noise: Because of the frequency of FM waves in extremely high, it is highly susceptible to effects from geological formations and buildings These effects disrupt the broadcast signal and obstruct reception in several ways

- Multipath noise
This describes the echo that occurs when the broadcast signal is reflected by a large obstruction and enters the receiver with a slight time delay relative to the direct signal (repetitious buzzing)
- Fading noise
This is a buzzing noise that occurs when the broadcast signal is disrupted by obstructing objects and the signal strength fluctuates intricately within a narrow range

Q: Is the problem station or location specific?

YES: The effect of an electrical field condition (multipath noise, fading noise) could be the cause Check that there is not noise

NO: Go to Step 3

STEP 3 Check that noise appears when the radio switch is turned on while the vehicle is stopped

NOTE: Body static electricity from the shock absorber rubber bushings used to prevent vibration, tires, etc occurs because of separation from the ground, causing a buzzing noise There is no measures to discharge the static electricity of the vehicle body Check that there is no noise

Q: Does noise appear when the radio switch is turned on while the vehicle is stopped and the radio is tapped while tuned away from a station?

YES: Go to Step 4

NO: It may be static electricity noise

STEP 4 Verify that the radio is correctly grounded

Q: Is the radio correctly grounded?

YES: Go to Step 5

NO: Check that there is no noise

STEP 5 Check by replacing radio and CD player or radio, CD player and CD changer

Q: Do the other radio and CD player or radio, CD player and CD changer work normally?

YES: Either repair or replace the original radio and CD player or radio, CD player and CD changer Check that there is no noise

NO: Either repair or replace the antenna assembly Check that there is no noise