Toyota Sienna Service Manual: Identification of noise source
1. Radio Description
- Radio frequency band
![Radio Description](images/books/424/62/index298.jpg)
- Radio broadcasts use the radio frequency bands
shown in the table below
- Service area
![Radio Description](images/books/424/62/index299.jpg)
- The service areas of AM and FM broadcasts are
vastly different. Sometimes an AM broadcast
can be received very clearly but an FM stereo
cannot. FM stereo has the smallest service area,
and is prone to pick up static and other types of
interference such as noise.
- Radio reception problems
HINT:
In addition to static, other problems such as
"phasing", "multipath", and "fade out" exist. These
problems are not caused by electrical noise, but by
the radio signal propagation method itself.
![Radio Description](images/books/424/62/index21.jpg)
- Phasing
AM broadcasts are susceptible to electrical
interference and another kind of interference
called phasing. Occurring only at night, phasing
is the interference created when a vehicle
receives 2 radio wave signals from the same
transmitter. One signal is reflected off the
ionosphere and the other signal is received
directly from the transmitter.
![Radio Description](images/books/424/62/index22.jpg)
- Multipath
Multipath is a type of interference created when
a vehicle receives 2 radio wave signals from the
same transmitter. One signal is reflected off
buildings or mountains and the other signal is
received directly from the transmitter.
![Radio Description](images/books/424/62/index23.jpg)
- Fade out
Fade out is caused by objects (buildings,
mountains, and other large obstacles) that
deflect away part of a signal, resulting in a
weaker signal when the object is between the
transmitter and vehicle. High frequency radio
waves, such as FM broadcasts, are easily
deflected by obstructions. Low frequency radio
waves, such as AM broadcasts, are much more
difficult to deflect.
- Noise problem
Technicians must have a clear understanding about
each customer's noise complaint. Use the following
table to diagnose noise problems.
Radio Frequency |
Noise Occurrence Condition |
Presumable Cause |
AM |
Noise occurs in a specified area |
Foreign noise |
AM |
Noise occurs when listening to an intermittent broadcast |
An identical program transmitted from
multiple towers can cause noise where the
signals overlap |
AM |
Noise occurs only at night |
Music beat from a distant broadcast |
FM |
Noise occurs while driving in a specified area |
Multipath or phasing noise resulting from a
change in FM frequency |
HINT:
If the noise does not match the examples above, refer to the
descriptions about phasing and multipath.
1 VEHICLE BROUGHT INTO A WORKSHOP
2 DIAGNOSTIC QUESTIONING AND SYMPTOM CONFIRMATION
Ask the customer about symptoms and confirm
malfunctions.
3 CONFIRM THE SYSTEM NORMAL CONDITION
4 CHECK D ...
1. CHECK NORMAL CONDITION
If the symptom is applicable to any of the following,
it is intended behavior, and not a malfunction.
Symptom
Answer
A longer route ...
Other materials:
SRS airbags
The SRS airbags inflate when the vehicle is subjected to certain
types of severe impacts that may cause significant injury to the
occupants. They work together with the seat belts to help reduce
the risk of death or serious injury.
SRS front airbags
SRS driver airbag/front passenger ...
Diagnostic trouble code chart
If a malfunction code is displayed during the DTC check,
check the circuit listed for that code in the table below.
(Proceed to the page given for that circuit.)
POWER BACK DOOR SYSTEM
DTC No.
Detection Item
Trouble Area
B2222
PBD Pulse Sensor Malfuncti ...
Audio system operation buttons
“AUDIO” button
Display the “Select Audio Source” screen or audio top screen.
“SETUP” button
Press this button to customize the function settings.
“CAR” button
Press this button to access the vehicle information.
button
Press this button to access the Blue ...