Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 554 (AUDIO & VISUAL SYSTEM - DIAGNOSTICS)PRE-CHECK

2004 Toyota Matrix XR, FWD, Standard

Section 554 (Audio & Visual System - Diagnostics): Pre-Check

2004 Toyota Matrix XR, FWD, StandardSECTION Pre-Check

WARNING: This page is about a different car, the 2003 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.

RADIO WAVE BAND
The radio wave bands used in radio broadcasting are as follows:

Fig 1: Radio Wave Band Frequency Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
SERVICE AREA
There are great differences in the size of the service area for AM and FM monaural. Sometimes FM stereo broadcasts cannot be received even through AM can be received in very clearly. Not only does FM stereo have the smallest service area, but it also picks up static and other types of interference ("noise") easily.

Fig 2: Identifying Service Area Difference
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
RECEPTION PROBLEMS
Besides the problem of static, there are also the problems called "fading", "multipath" and "fade out". These problems are caused not by electrical noise but by the nature of the radio waves themselves.
1. Fading:
  Besides electrical interference, AM broadcasts are also susceptible to other types of interference, especially at night. This is because AM radio waves bounce off the ionosphere at night. These radio waves then interfere with the signals from the same transmitter that reach the vehicle's antenna directly. This type of interference is called "fading".
  
  Fig 3: Identifying Fading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Multipath:
  One type of interference caused by the bounce of radio waves off of obstructions is called "multipath". Multipath occurs when a signal from the broadcast transmitter antenna bounces off buildings and mountains, interfering with the signal that is received directly.
  
  Fig 4: Identifying Multipath
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Fade Out:
  Because FM radio waves are of higher frequencies than AM radio waves, they bounce off buildings, mountains, and other obstructions. For this reason, FM signals often disappear or fade away gradually as the vehicle goes behind a building or other obstruction. This is called "fade out".
Fig 5: Identifying Fade Out
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOISE PROBLEMS
1. Questionnaire for noise:
  It is very important for noise troubleshooting to have good understanding of the claims from the customers. Refer to the following questionnaire to diagnose the problem accurately.
  
  Fig 6: Noise Problems Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002