Inspection Procedure 6

Inspection Procedure 6: Poor Reception.

CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit, and the communication circuit are normal.(Check that the voltage is 10 V or more.)

COMMENTS ON TROUBLE SYMPTOM
In case of poor reception, the roof antenna (antenna rod, antenna base), antenna feeder, or multivision display may have a problem.

NOTE: The radio wave may not be received if the vehicle is placed in the area which is exposed to a special electric field. Thus, check that the radio broadcasting can be received using the radio of another vehicle before carrying out diagnosis.

PROBABLE CAUSES
- The roof antenna (antenna rod, antenna base) may be defective
- The antenna feeder may be defective
- The multivision display may be defective
- Damaged harness wires and connectors

DIAGNOSIS

STEP 1. Check the state of the roof antenna.

Q : Is the roof antenna assembled?

YES : Go to Step 2.

NO : Assemble the antenna. Check that a poor reception is resolved.

STEP 2. Check to see if inspections are taking place is an area exposed to special electric fields.

Q : Are inspections taking place under special electric field conditions (underground garage, inside a building, etc.)?

YES : Go to Step 3.

NO : Go to Step 4.

STEP 3. Move the vehicle and check the radio.

Move the vehicle to a good reception area that is not exposed to special electric fields.

Q : Is reception of the strongest radio frequency possible within the area?

YES : Check that a poor reception is resolved.

NO : Go to Step 4.

STEP 4. Tune the radio, and then check it.

Q : Did the sensitivity improve after tuning?

YES : Check that a poor reception is resolved.

NO : Go to Step 5.

STEP 5. Check with several broadcasting stations.

NOTE: Two types of noise are addressed in this procedure, multipath and fading noise. The frequency of FM waves is extremely high. This makes them susceptible to effects from geological formations and buildings. These effects disrupt the broadcast signal and obstruct reception in many ways.

- Multipath noise is the echo that occurs when the broadcast signal is reflected by a large obstruction and enters the receiver with a slight time delay relative to the direct signal (repetitious buzzing).
- A fading or buzzing noise may occur when the broadcast beam is disrupted by obstructing objects and the signal strength fluctuates within a narrow range.

Q : Is the abnormality in reception generated only within a certain range?

YES : Check that a poor reception is resolved.

NO : Go to Step 6.

STEP 6. Check the connection of the antenna plug and multivision display.

Q : Is the antenna plug thoroughly connected to the multivision display?

YES : Go to Step 7.

NO : Thoroughly connect the antenna plug and the multivision display. Check that a poor reception is resolved.

STEP 7. Check by replacing multivision display.

Q : Do the other multivision display work normally?

YES : Either repair or replace the original multivision display. Check that a poor reception is resolved.

NO : Either repair or replace the antenna assembly. Check that a poor reception is resolved.