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Mazda CX 7. Manual - part 364

SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–7

09-03E

End Of Sie

• Measure battery voltage.

• Is battery voltage okay?

Standard

With ignition switch ON: 11.5 V or more
At idling: 12.5 V or more

Note

• Inspect that battery cables are connected

to terminals securely.

Yes

Go to the next step.

Charge battery. Inspect charging system, and repair or
replace if necessary.

• Is noise occurring only when vehicle

electrical system (e.g. fuel pump) operates?

Note

• Identify subject electrical component by

disconnecting fuse, turning switch ON &
OFF, or disconnecting & connecting
connector.

• It will be easy when simulation function on

M-MDS is used.

Yes

Go to the next step.

Go to the Step 8.

• Inspect power supply, ground condition, and

noise prevention capacitor for electrical
component.

• Is noise present after inspection?

Note

• Inspect following:

— Power supply to electrical component

for voltage drop (compare with battery
voltage)

— Resistance between ground of

electrical component and body.
(Should be close to 0 ohm)

— Installation condition of noise

prevention capacitor for fuel pump etc.

Yes

Go to the next step.

Troubleshooting completed.

• Inspect antenna plug connection condition.

• Is connection okay?

Yes

Go to the next step.

Insert antenna plug securely.

• Turn ignition switch to LOCK position.

• Measure continuity between antenna feeder

axis and ground.

• Is there any continuity?

Yes

Replace antenna feeder.

Go to the next step.

• Compare reception with other audio unit on

same model (model/unit) under same
problem conditions.

• Is reception equivalent between customer’s

unit and compared unit?

Yes

The system is normal (It is caused by electronic jamming
from outside, or inferior broadcasting station signal
condition).

Go to the next step.

• Retighten ground fixation for antenna

installation part and antenna amplifier.
Retighten antenna rod.

• Is noise present, after retightening?

Note

• When antenna is not grounded perfectly,

FM particular noise is likely to be
conspicuous.

Yes

Replace audio unit.

Troubleshooting completed.

STEP

INSPECTION

ACTION

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–8

NO.4 CANNOT TUNE (SEEK DOES NOT STOP)[RADIO]

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Diagnostic procedure

End Of Sie

Cannot tune (SEEK does not stop)/Possible DTC: 09:Er20, 09:Er22

POSSIBLE
CAUSE

• Center panel malfunction

• Antenna plug poor connection

• Antenna feeder malfunction

• Audio unit malfunction

• Electronic jamming from outside, or inferior condition of broadcasting station radio wave

• Antenna rod not installed

STEP

INSPECTION

ACTION

• Inspect if feel of SEEK button is normal when

button is pushed and released.

• Is it okay?

Yes

Go to the next step.

Perform confirmation step 1: audio panel switch
confirmation. Replace center panel if necessary.

• Inspect indication of LCD.

• Is frequency indication increased or

decreased when SEEK button is pushed?

Yes

Go to the next step.

Perform confirmation step 1: audio panel switch
confirmation. Replace center panel if necessary.

• Manually tune to local broadcasting station

and check reception condition.

• Is reception okay?

Yes

Go to the Step 6.

Go to the next step.

• Inspect antenna plug connection condition.

• Is connection okay?

Yes

Go to the next step.

Insert antenna plug securely.

• Turn ignition switch to LOCK position.

• Measure continuity between antenna feeder

axis and ground.

• Is there any continuity?

Yes

Replace antenna feeder.

Go to the next step.

• Check if number of broadcasting stations

changes depending on time and place.

• Does it change?

Yes

The system is normal. (Explain to customer that SEEK
sometimes does not stop depending on signal reception
condition.)

Note

• Signals tend to reach longer distances at night. It is

conspicuous in AM signals, several audio functions
may stop due to foreign broadcasting station or noise.
Though the audio system restrains sensitivity of
SEEK and SCAN functions at night, the audio system
may select other than desired broadcasting station
when signals are considerably strong.This function is
linked to the parking light. When the parking light or
headlight is turned on, SEEK and SCAN may not
function for weak signals.

Replace audio unit.

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–9

09-03E

NO.5 CANNOT PRESET (PRESET FUNCTION DOES NOT OPERATE)[RADIO]

id0903e3804700

Diagnostic procedure

End Of Sie

NO.6 RECEPTION FREQUENCY OF RADIO SLIPS[RADIO]

id0903e3804800

Diagnostic procedure

End Of Sie

Cannot preset (preset function does not operate)/Possible DTC: 21:Er19

POSSIBLE
CAUSE

• Audio unit malfunction

• Center panel malfunction

STEP

INSPECTION

ACTION

• Tune to desired station and push channel

preset button 1 for about 2 seconds to store
it.

• Repeat above for other stations using

channel preset buttons 2 to 5.

• Push channel preset button 1 to 6 one by

one.

• Are stored stations present?

Yes

Go to the next step.

Go to the Step 3.

• Turn ignition switch to LOCK and then to

ACC.

• Check if preset stations are stored by

pushing preset buttons.

• Are stations stored?

Yes

The system is normal. (Explain preset procedure to
customer using Owner’s Manual)

Replace audio unit.

• Remove center panel from audio unit, and

reinstall center panel to audio unit.

• Turn audio power switch ON.

• Press the POWER button and

simultaneously press the CLOCK button for
approx. 1s.

• Push all buttons and check if buzzer sounds.

• Are all buttons okay?

Yes

Replace audio unit.

Replace center panel.

Reception frequency of radio slip/Possible DTC: 09:Er22

POSSIBLE
CAUSE

• Audio unit malfunction

• Electronic jamming from outside, or inferior condition of broadcasting station radio wave

STEP

INSPECTION

ACTION

• Push SEEK button and check if desired

broadcasting station is tuned.

• Is it okay?

Yes

Go to the Step 3.

Go to the next step.

• Check if other broadcasting station is

received at certain place when indication of
reception frequency stays.

• Is other station received?

Note

• When you receive weak signal from one

broadcasting station and come close to
broadcasting antenna which emits strong
signal, broadcasting with strong signal is
sometimes received.

Yes

Go to the next step.

Replace audio unit.

• Compare reception with other audio unit on

same model (model/unit) under same
problem conditions.

• Is reception equivalent between customer’s

unit and compared unit?

Yes

Troubleshooting completed (Audio unit is normal).

Replace audio unit.

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–10

REFERENCE[RADIO]

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1. Multipath Noise

• Signals from an FM transmitter are a high

frequency and similar to beams of light because
they do not bend around corners, but they do
reflect. Since FM signals can be reflected by
obstructions, it is possible to receive both the
direct signal and the reflected signal at the same
time. This causes a slight delay in reception and
may be heard as a broken sound or a distortion.

2. Flutter/Skip Noise

• Signals become weak in valleys between

mountains, tall building, and other obstacles.
When the vehicle passes through such an area,
the reception conditions may change suddenly,
resulting in annoying noise.

3. Stereo and Monaural Receptions

• As signals become weak, noise may appear more in stereo reception. Comparing to stereo reception, noise in

monaural receptions is relatively less striking.

Measures in Audio System
Separation control

• Utilizing the characteristic of monaural reception that noise is relatively less striking than stereo reception, the

audio system automatically changes the reception from stereo to monaural and lessens annoying noise when
signals become weak or a multipath phenomenon occurs.

High tone control

• When signals become weak or a multipath phenomenon occurs, the audio system restrains volume level in

high frequency band and lessens annoying noise.

Effect Setting of Separation Control and High Tone Control

• The separation and high tone controls influence sound quality, Therefore they are specifically tuned for

individual model. (Comparison of characteristic must be done on the same models)

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Noise restraint setting

High tone setting

Wider effective range

Less effective range

Noise is less conspicuous

Noise is conspicuous

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