Mazda CX 7. Manual — part 363

SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–3

09-03E

CONFIRMATION STEP 2: ANTENNA SYSTEM SYMPTOM (EXAMPLE)[RADIO]

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End Of Sie

CONFIRMATION STEP 3: ANTENNA SYSTEM SIMPLE INSPECTION[RADIO]

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• Because the antenna system is equipped with a capacitor, the continuity cannot be checked. Therefore

proceed with the following simple inspection.

1. Turn the AM radio on.
2. Tune to the frequency that there is no broadcast and you will hear a buzzing sound.
3. Turn a fluorescent light on and shake it around the antenna rod (around 10—20 mm)

Note

• Use a fluorescent light type for the

inspection. Accurate diagnostic cannot be
done with a different type of light.

4. If a whirring sound from the speaker

synchronized to the work light movement is
confirmed, the antenna system is normal.

End Of Sie

NO.1 NO RADIO RECEPTION (AM/FM)/NO OR LOW VOLUME[RADIO]

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Diagnostic procedure

Possible cause

AM reception condition

FM reception condition

• Antenna feeder axis, open circuit

• Antenna feeder plug not attached

NG: No reception

YES: Reception possible.
(Sensitivity decreases, but reception is
possible under strong electric field.)

• Antenna feeder axis (+) to ground (-), open circuit NG: No reception

NG: No reception

• Antenna feeder and antenna, poor ground

YES: Reception possible
(Noise may occur)

YES: Reception possible
(Sensitivity decreases, but reception is
possible under strong electric field.)

• Antenna feeder, jack and plug poor connection

NG: No reception
(Depending on connection
conditions)

YES: Reception possible
(Depending on connection conditions)

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1

No radio reception (AM/FM)/no or low volume/Possible DTC: 09:Er20, 09:Er22

POSSIBLE
CAUSE

• Jamming from aftermarket electronic equipment (two-way radio, navigation system, mobile phone, etc.)

• Audio unit malfunction

• Antenna plug poor connection

• Antenna feeder malfunction

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

• Antenna rod is not installed

STEP

INSPECTION

ACTION

1

• Turn the audio unit ON.

• Is the LCD indicated correctly?

Yes

Go to the Step 3.

No

Go to the next step.

2

• Measure voltage at B+ and ACC terminals.

• Is voltage okay?

Specification

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

Yes

Go to the next step.

No

Follow diagnostic procedure for symptom No. 2 (Entire
audio system).

3

• Set volume to 10 to 15.

• Is buzzing sound or voice confirmed?

Yes

Go to the next step.

No

Follow diagnostic procedure for symptom No. 3 (Entire
audio system) or No. 4 (Entire audio system).

4

• Tune to local broadcasting station and check

reception condition.

• Is reception okay?

Yes

Go to the next step.

No

Go to the Step 6.

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–4

End Of Sie

5

• Push PRESET buttons and check preset

conditions.

• Has preset been stored?

Yes

The system is normal.

No

Preset broadcasting stations.

6

• Is aftermarket electronic equipment (two-way

radio, navigation system, mobile phone, etc.)
installed?

Note

• TV antenna located closely to audio

antenna can be cause of noise. Relocate
TV antenna.

Yes

Go to the next step.

No

Go to the Step 8.

7

• Remove aftermarket electronic equipment.

• Turn audio unit ON and check reception

condition.

• Is reception improved?

Yes

The system is normal.
(Explain to customers that aftermarket electronic equipment
is cause of noise)

No

Go to the next step.

8

• Refer to confirmation step 3, and inspect

antenna system.

• Is a whirring sound present?

Yes

Replace audio unit.

No

Go to the next step.

9

• Inspect antenna plug connection condition.

• Is connection okay?

Yes

Go to the next step.

No

Insert antenna plug securely.

10

• Turn ignition switch to LOCK position.

• Measure continuity between antenna feeder

axis and ground.

• Is there any continuity?

Yes

Replace antenna feeder.

No

Go to the next step.

11

• 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?

Note

• Due to following differences, you may feel

difference in reception efficiency.

(Vehicle side factor)

— Antenna installation location, height,

feeder wiring routing, optional electrical
equipment

(Audio unit factor)

— Volume concern type: It decreases

change of volume when signals
become weak. (Noise is conspicuous)

— Noise decrease type: It decreases

volume when signals become weak, so
that noise is not conspicuous.

Yes

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

No

Replace audio unit.

STEP

INSPECTION

ACTION

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–5

09-03E

NO.2 NOISE FROM RADIO (AM ONLY)[RADIO]

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Diagnostic procedure

2

Noise from radio (AM only)/Possible DTC: 09:Er22

POSSIBLE
CAUSE

• Antenna rod not installed

• Jamming from aftermarket electronic equipment (two-way radio, navigation system, mobile phone, etc.)

• Noise from electrical system on vehicle (e.g. fuel pump)

• Battery malfunction

• Charging system malfunction

• Audio unit malfunction

• Antenna plug poor connection

• Antenna feeder malfunction

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

• Antenna installation loosened

STEP

INSPECTION

ACTION

1

• Tune to local broadcasting station and check

reception condition.

• Is reception okay?

Yes

Tune to correct frequency of broadcasting station.
If not preset, preset it.

No

Go to the next step.

2

• Inspect antenna rod condition.

• Is antenna rod installed?

Yes

Go to the next step.

No

Advise customer to install antenna rod when radio is used.

3

• Is aftermarket electronic equipment (two-way

radio, navigation system, mobile phone, etc.)
installed?

Note

• TV antenna located closely to audio

antenna can be cause of noise. Relocate
TV antenna.

Yes

Go to the next step.

No

Go to the Step 5.

4

• Remove aftermarket electronic equipment.

• Turn audio unit ON and check reception

condition.

• Is reception improved?

Yes

The system is normal. (Explain to customers that
aftermarket electronic equipment is cause of noise)

No

Go to the next step.

5

• 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.

No

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

6

• 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.

No

Go to the Step 8.

7

• 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.

No

Troubleshooting completed.

Note

• The audio unit supplies 12 V battery power to the

antenna amplifier for the AM radio reception in the
radio mode. The audio unit cannot receive the AM
signals without the 12 V battery power to the antenna
amplifier. If the AM signals become strong, the audio
unit may receive the signal with noises.

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SYMPTOM TROUBLESHOOTING [RADIO]

09-03E–6

End Of Sie

NO.3 NOISE FROM RADIO (FM ONLY)[RADIO]

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Diagnostic procedure

8

• Inspect antenna plug connection condition.

• Is connection okay?

Yes

Go to the next step.

No

Insert antenna plug securely.

9

• Turn ignition switch to LOCK position.

• Measure continuity between antenna feeder

axis and ground.

• Is there any continuity?

Yes

Replace antenna feeder.

No

Go to the next step.

10

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?

Note

• Due to following differences, you may

detect a difference in reception efficiency.

(Vehicle side factor)

— Antenna installation location, height,

feeder wiring routing, optional electrical
equipment

(Audio unit factor)

— Volume concern type: It decreases

change of volume when signals
become weak. (Noise is conspicuous)

— Noise decrease type: It decreases

volume when signals become weak, so
that noise is not conspicuous.

Yes

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

No

Go to the next step.

11

• Retighten ground fixation for antenna

installation part and antenna amplifier.
Retighten antenna rod.

• Is noise present, after retightening?

Yes

Replace audio unit.

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

3

Noise from radio (FM only)/Possible DTC: 09:Er22

POSSIBLE
CAUSE

• Antenna rod not installed

• Jamming from aftermarket electronic equipment (two-way radio, navigation system, mobile phone, etc.)

• Noise from electrical system on vehicle (e.g. fuel pump)

• Battery malfunction

• Charging system malfunction

• Audio unit malfunction

• Antenna plug poor connection

• Antenna feeder malfunction

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

• Antenna installation loosened

Note

• FM broadcast has feature “sound quality is good” and “resistant to noise”, but FM broadcast has particular

noises. Though audio unit is designed to reduce noise, there are times noise occurs due to conditions.

STEP

INSPECTION

ACTION

1

• Tune to local broadcasting station and check

reception condition.

• Is reception okay?

Yes

Tune to correct frequency of broadcasting station.
If not preset, preset it.

No

Go to the next step.

2

• Inspect antenna rod condition.

• Is antenna rod installed?

Yes

Go to the next step.

No

Advise customer to install antenna rod when radio is used.

3

• Is aftermarket electronic equipment (two-way

radio, navigation system, mobile phone, etc.)
installed?

Yes

Go to the next step.

No

Go to the Step 5.

4

• Remove aftermarket electronic equipment.

• Turn audio unit ON and check reception

condition.

• Is reception improved?

Yes

The system is normal. (Explain to customers that
aftermarket electronic equipment is cause of noise)

No

Go to the next step.

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