| 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 |
- 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 4. |
| 3 |
- 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. |
| 4 |
- Measure battery voltage.
- Is battery voltage okay?
Specification:
- 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. |
| 5 |
- 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 Step 7. |
| 6 |
- Inspect power supply, ground condition, and noise prevention capacitor for electrical component.
- Is noise present after inspection?
NOTE:
- Inspect the 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.
|
| 7 |
- Inspect antenna feeder connection condition.
- Is connection okay?
|
Yes |
Go to the next step. |
| No |
Insert antenna feeder securely. |
| 8 |
- Switch the ignition OFF (LOCK).
- Measure continuity between antenna feeder axis and ground.
- Is there any continuity?
|
Yes |
Replace antenna feeder.
(See ANTENNA FEEDER NO.1 REMOVAL/INSTALLATION
.)
(See ANTENNA FEEDER NO.2 REMOVAL/INSTALLATION
.) |
| No |
Go to the next step. |
| 9 |
- 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 |
Go to the next step. |
| 10 |
- Retighten ground fixation for antenna installation part and antenna amplifier.
- Is noise present, after retightening?
|
Yes |
Replace audio unit.
(See AUDIO UNIT REMOVAL/INSTALLATION
.) |
| No |
Troubleshooting completed. |