Audio System - Diagnosis: Other Lexus RX II

PRECAUTION

Note. When disconnecting the negative (-) battery terminal, initialize the following systems after the terminal is reconnected.

SYSTEM NAMES

Scheme 64

Scheme 65

Scheme 66

Scheme 67

Scheme 68

Scheme 69

Scheme 70

Scheme 71

1. RADIO WAVE BAND The radio wave bands used in radio broadcasting are as follows: RADIO WAVE BANDS SPECIFICATION CHART Frequency 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz Designation LF MF HF VHF Radio wave AM <----> FM <----> Modulation Amplitude modulation Frequency modulation LF: Low Frequency MF: Medium Frequency HF: High Frequency VHF: Very High Frequency
2. SERVICE AREA There is a great difference in the size of the service areas for AM and FM broadcasting. Sometimes an FM stereo broadcast cannot be received even though AM can be received very clearly. FM stereo has the smaller service area, it also picks up static and other types of interference ("noise") easily.
3. RECEPTION PROBLEMS HINT: Besides the problem of static, there are other problems called "fading", "multipath" and "fade out". These problems are caused not by electrical noise but by the nature of the radio waves themselves. 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 that reach the vehicle's antenna directly from the same transmitter. This type of interference is called "fading". Multipath Interference caused by reflection of radio waves against obstructions is called "Multipath". Multipath occurs when radio signals emitted from the broadcast transmitter antenna are reflected against tall buildings or mountains and interferes with other signals which are to be received directly. Fade Out FM radio wave tends to be reflected against obstructions such as tall buildings or mountains because FM frequency is higher than that of AM. For this reason, FM signals often seem to gradually disappear or fade away as the vehicle goes behind those obstructions. This phenomenon is called "fade out".
4. NOISE PROBLEMS It is very important for technicians to understand a customer's claim about noise clearly. Use «NOISE CAUSE DESCRIPTION CHART»(ref-215928-S41936603652006011900000) to diagnose the phenomena. NOISE CAUSE DESCRIPTION CHART Radio wave Condition in which noise occurs Probable cause AM Noise occurs at a specific place. Strong possibility of foreign noise. Noise occurs when listening to faint broadcasting. The same program may be broadcasted from some local stations. If the program is the same, one of those may be tuned in. FM Noise occurs only at night. Strong possibility of beat from a distant broadcasting. Noise occurs at a specific place during driving. Strong possibility of multipath noise and fading noise caused by changes of FM frequency. HINT: If the condition when the noise occurs does not meet any of the above, find out the cause based on "Reception Problems". Refer to 3 .
5. COMPACT DISC PLAYER Compact Disc Players (hereafter called "CD") use a laser beam pick-up to read the digital signals recorded on the CD and reproduce analog signals of the music, etc. 4.7 in. (12 cm) and 3.2 in. (8 cm) discs are available for the CD player. HINT: Never disassemble or apply oil to any part of the player unit. Do not insert any object other than a disc, into the CD player. NOTE: CD players use an invisible laser beam which could cause hazardous radiation exposure. Be sure to operate the player correctly as instructed.
6. MAINTENANCE Tape Player / Head Cleaning: Raise the cassette door with your finger. Using a pencil or similar object, push in the guide. Using a cleaning pen or cotton applicator soaked in cleaner, clean the head surface, pinch rollers and capstans.
7. MAINTENANCE CD Player / Disc Cleaning: If the disc gets dirty, clean the disc by wiping the surface from the center to outside in the radial directions with a soft cloth. NOTE: Do not use a conventional record cleaner or anti-static preservative.
8. OUTLINE OF AVC-LAN What is AVC-LAN? AVC-LAN is the abbreviation for Audio Visual Communication-Local Area Network. This is a unified standard co-developed by 6 audio manufacturers associated with Toyota Motor Corporation. The unified standard includes signals, such as audio, visual and signals for switch indication and communication. Objectives Recently development in car audio systems has been rapid and functions have been changed drastically. The conventional system has been switched to the multi-media type such as a navigation system. At the same time customers wants to upgrade their audio systems. This is the factor that lies behind this standardization. The concrete objectives are explained below. When products by different manufacturers were combined together, malfunctions such as sound failure occurred. This problem can be solved by standardization of signals. Various types of after market products are available. Because of the above (2), each manufacturer has been able to concentrate on developing products in their strongest field. This has enabled the development of inexpensive products. In general, a new product developed by a particular manufacturer could not be used due to a lack of compatibility with other manufacturer's products. By developing this new standard, users can enjoy a range of compatible products from different manufacturers. The above stated are the reasons for the introduction of AVC-LAN. Under this standardization, development of new products no longer causes systematic errors. HINT: When +B short or GND short is detected in the AVC-LAN circuit, communication stops, and the audio system does not function normally. When the audio system is not equipped with a navigation system, the audio head unit is the master unit. When the audio system is equipped with a navigation system, the multi-display is the master unit. The radio receiver assy is equipped with a resistor (60 to 80 ohm) for communication. The car audio system using AVC-LAN circuit has a diagnostic function. Each product has its own specified number called a physical address (three-digit number). Numbers are also allotted to each function with a product, which are called logical addresses (two-digit number).
9. COMMUNICATION SYSTEM Components in the audio system communicate each other through AVC-LAN. (Radio receiver with CD changer control function) The master component of AVC-LAN is the radio receiver assy with a resistor (60 to 80 ohm), which is necessary for communication. When a short circuit or circuit breakdown occurs in the AVC-LAN circuit, the audio system does not operate normally due to the communication cutoff.
10. DIAGNOSTIC FUNCTION The audio system has diagnostic function (The diagnostic result is displayed on the LCD of the radio receiver assy). (Radio receiver with CD changer control function) The component code (physical address), or three-digit number (in hexadecimal) is set for each component comprising AVC-LAN. The logical address, or two-digit number (in hexadecimal) is set for each function and component unit in each component.

RADIO RECEIVER ASSY

RADIO RECEIVER ASSY PROBLEM SYMPTOMS

STEERING PAD SWITCH

STEERING PAD SWITCH PROBLEM SYMPTOMS