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

Possible DTC	No radio reception (AM/FM)/no or low volume
Possible cause	• Low vehicle battery voltage • Electronic jamming from outside, or inferior condition of broadcasting station radio wave • Jamming from aftermarket electronic equipment (two-way radio, navigation system, mobile phone, etc.) • Antenna plug poor connection • Antenna feeder malfunction • Audio unit malfunction

Possible DTC

No radio reception (AM/FM)/no or low volume

Using the M-MDS

U3000:16, U3000:04

Without using M-MDS (On-board diagnostic test mode)

09:Er20, 09:Er22

Possible cause

• Low vehicle battery voltage

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

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

• Antenna plug poor connection

• Antenna feeder malfunction

• Audio unit malfunction

STEP	INSPECTION	ACTION
1	• Can the location where the malfunction occur be specified?	Yes	The system is normal. Explain to the customer that the noise is caused by radio wave disturbances or broadcast wave conditions from the outside.
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 AUDIO POWER IS NOT AVAILABLE OR SWITCHED ON OR OFF AUTOMATICALLY [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 SOUND FROM ALL SPEAKERS [ENTIRE AUDIO SYSTEM] or NO SOUND FROM SOME SPEAKERS [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 Step 6.
5	• Push PRESET switches 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 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. (See AUDIO UNIT REMOVAL/INSTALLATION.)
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	• Switch the ignition off (LOCK). • 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 easily noticed) ― Noise decrease type: It decreases volume when signals become weak, so that noise is not noticeable.	Yes	The system is normal. (It is caused by electronic jamming from outside, or inferior broadcasting station signal condition.)
No	Replace audio unit. (See AUDIO UNIT REMOVAL/INSTALLATION.)

STEP

INSPECTION

ACTION

• Can the location where the malfunction occur be specified?

Yes

The system is normal. Explain to the customer that the noise is caused by radio wave disturbances or broadcast wave conditions from the outside.

Go to the next step.

• 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.

Follow diagnostic procedure for symptom AUDIO POWER IS NOT AVAILABLE OR SWITCHED ON OR OFF AUTOMATICALLY [ENTIRE AUDIO SYSTEM].

• Set volume to 10 to 15.

• Is buzzing sound or voice confirmed?

Yes

Go to the next step.

Follow diagnostic procedure for symptom NO SOUND FROM ALL SPEAKERS [ENTIRE AUDIO SYSTEM] or NO SOUND FROM SOME SPEAKERS [ENTIRE AUDIO SYSTEM].

• Tune to local broadcasting station and check reception condition.

• Is reception okay?

Yes

Go to the next step.

Go to Step 6.

• Push PRESET switches and check preset conditions.

• Has preset been stored?

Yes

The system is normal.

Preset broadcasting stations.

• 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.

Go to Step 8.

• 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)

Go to the next step.

• Refer to confirmation step 3, and inspect antenna system.

• Is a whirring sound present?

Yes

Replace audio unit.

(See AUDIO UNIT REMOVAL/INSTALLATION.)

Go to the next step.

• Inspect antenna plug connection condition.

• Is connection okay?

Yes

Go to the next step.

Insert antenna plug securely.

• Switch the ignition off (LOCK).

• 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?

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 easily noticed)

― Noise decrease type: It decreases volume when signals become weak, so that noise is not noticeable.

Yes

The system is normal.

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

Replace audio unit.

(See AUDIO UNIT REMOVAL/INSTALLATION.)