Mazda CX-7 2007 Workshop Manual page 1432

SYMPTOM TROUBLESHOOTING [ENTIRE AUDIO SYSTEM]
NO.1 AF NOISE OR POP NOISE ON ALL SOURCES (RADIO, CD, CASSETTE TAPE)[ENTIRE AUDIO
SYSTEM]
1 AF noise or POP noise on all sources (Radio, CD, Cassette tape)/Possible DTC: 09:Er20, 09:Er21
Troubleshooting hints
• Low vehicle battery voltage.
• Jammed radio signals from after market equipment.
• Speaker malfunction (e.g., any foreign material, broken)
• Improper speaker installation
• Audio unit malfunction
• Poor connection of audio unit connector, terminal damage
• Poor connection of audio amplifier connector, terminal damage (with Bose)
• Antenna malfunction (e.g., poor ground)
Note
• AF noise is a snapping noise that generally occurs during ON/OFF switching operations of electrical equipment other
than the audio unit, or a continual rasping noise that occurs when electrical equipment is operated. This is caused by
noise interference in the power supply wiring, signal wiring, speaker cable or head of cassette deck. Therefore noise can
be heard regardless of radio wave conditions or the audio volume position. The noise will start after one click from the
minimum position of the volume button but normally does not change even when volume is turned to a higher position.
• POP noise is snapping or popping noise that occurs during ON/OFF switching operation of the audio unit, or when
switching from radio to CD. Even a normal audio unit sometimes emits a little noise depending on the conditions.
Diagnostic procedure
STEP
• Inspect the vehicle battery voltage.
1
• Is the vehicle battery voltage normal?
Specification:
Ignition switch ON: 11.5 V or more
Idle: 12.5 V or more
• Turn the audio system to ON.
2
• Is there any noise?
• Is any of the following after-market
3
equipment installed? (Inspect especially near
the antenna.)
— Radar
— Remote engine starter
— Anti-theft device
— Other
• Remove the after-market equipment.
4
• Turn the audio system to ON.
• Is there any noise?
• Is there the noise from all speakers?
5
• Inspect the suspect speaker.
6
• Is the speaker normal?
• Attempt to duplicate the symptom on the
7
other vehicle.
• Is the noise better than the customer's
vehicle?
09-03D–4
INSPECTION
Yes Go to the next step.
No Charge the battery, then go to the next step.
Yes Go to the next step.
No The system is normal. Explain to the customer that the
vehicle battery voltage was low.
Yes Go to the next step.
No Go to the Step 5.
Yes Go to the next step.
No The system is normal. The after-market electrical devices
might make a noise.
Yes Go to the Step 7.
No Go to the next step.
Yes Go to the next step.
No If there is any foreign material on the speaker:
• Remove the foreign material from the speaker.
If the speaker is malfunctioning:
• Replace the speaker.
If the speaker is not installed properly:
• Install the speaker properly.
Yes Go to the next step.
No The system is normal. Explain the noise generation
mechanism to the customer.
Note
• The noise may be heard depends on the operating
speed of audio power and/or mode switch.
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ACTION