Mazda CX-7 2007 Workshop Manual page 1448

Quick Diagnostic Chart (Radio)
Possible factor
Jamming from aftermarket electronic equipment (two-way radio, navigation system, mobile phone, etc)
Audio unit
Antenna plug poor connection
Antenna feeder
Electronic jamming from outside, or inferior condition of broadcasting station radio wave
Antenna rod not installed
Noise from electrical system on vehicle (e.g. fuel pump)
Battery
Charging system
Antenna installation loosened
Center panel
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CONFIRMATION STEP 1: RECEPTION CONDITION SYMPTOM (EXAMPLE)[RADIO]
Symptom
Only a buzzing sound from
the speakers
A buzzing or crunching sound
and normal sound produced
at the same time from the
speakers
A thumping sound and
normal sound produced at the
same time from the speakers
(FM only)
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09-03E–2
SYMPTOM TROUBLESHOOTING [RADIO]
Antenna signal condition
• There is no broadcasting wave.
• Signals from antenna to audio unit are not
transmitted.
• Though signals are transmitted from
antenna to audio unit, electric noise from
other sources is larger.
• Noise occurs due to radio wave
environment at specific places (e.g. in
valleys between buildings). Noise varies
when own vehicle or surrounding vehicles
moves. (FM only)
Troubleshooting item
• Electric noise caused by the operation of
internal circuit from audio unit itself
• Atmosphere noise
• Electrical noise caused by operation of
electrical component on vehicle
• Electrical noise from high tension wire,
transformer substation (factory), electrical
feeder line (street car), or motorcycle.
• Interference between direct and reflected
waves of FM signals causes noise
(Multipass noise).
X: Applicable
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X X X
X X X X X X
X X X X
X X X X
X X X X X
X X X X
X X
X X
X X
X X
X X
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