Audio System & Visual System: Overview Toyota Tacoma II

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1. COMPACT DISC PLAYER Compact Disc (hereafter called CD) players use a laser beam pick-up to read the digital signals recorded on CDs 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 objects other than discs 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.
2. MAINTENANCE CD Player/Disc Cleaning If the disc gets dirty, clean the disc by wiping the surface from the center to the outside, in a radial direction, with a soft cloth (Scheme 5) NOTE: Do not use a conventional record cleaner or anti-static preservative.
3. OUTLINE OF AVC-LAN What is AVC-LAN? AVC-LAN is an 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 Recent development in car audio systems has been rapid and functions have been changed drastically. The conventional system has been switched to a multimedia type such as the navigation system. At the same time customers want to upgrade their audio systems. This is the factor that lies behind this standardization. The concrete objectives are explained below. When products of different manufacturers are combined together, malfunctions such as sound failure can occur. This problem can be solved by the standardization of signals. Various types of after market products are available. In general, new products developed by particular manufacturers 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. HINT: When a +B short or GND short is detected in the AVC-LAN circuit, communication stops, and the audio system does not function. 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 assembly is equipped with a resistor (60 to 80 ) for communication. All car audio systems using AVC-LAN circuits have diagnostic functions. Each unit has its own specified number called a physical address (three-digit number). Numbers are also allotted to each function, which are called logical addresses (two-digit number). COMMUNICATION SYSTEM Components in the audio system communicate with each other through the AVC-LAN. (Radio receiver with CD changer control function) 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. DIAGNOSTIC FUNCTION The audio system has a diagnostic function (the diagnostic result is displayed on the LCD of the radio receiver assembly). (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. DIAGNOSTIC TROUBLE CODE TABLE DIAGNOSTIC TROUBLE CODE TABLE Terms Description Physical address Three-digit code (shown in hexadecimal) which is given to each component comprising AVC-LAN. Corresponding to the function, individual symbols are specified. Logical address Two-digit code (shown in hexadecimal) which is given to each function comprising inner system of AVC-LAN. HINT: Titles for each unit are stated in the following order: physical address (part name). 190 (RADIO RECEIVER ASSEMBLY) Logical address: 01 (Communication control) LOGICAL ADDRESS - COMMUNICATION CONTROL DTC Diagnosis Item Diagnostic Content Troubleshooting D5 *1 Registered Component Disconnected Component shown by sub code is or was disconnected from system with ignition switch in ACC or ON. Communication with component shown by sub code is not ensured when engine is started. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. D6 *1 Absence of Master Component in which this code is recorded was disconnected from system or master component with ignition switch in ACC or ON. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. D7 *5 Connection Check Error Component in which this code is recorded was disconnected from system or master component with ignition switch in ACC or ON. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. D8 *2 No Response to Connection Check Component shown by sub code is or was disconnected from system after engine start. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. D9 *1 Last Mode Error Audio or visual component operated before engine stop is or was disconnected with ignition switch in ACC or ON. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. DA No Response to ON/OFF Instruction No response is identified when changing mode (audio and visual mode change). Sound and picture do not change by button operation. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. If error occurs again, replace component shown by sub code. DB *1 Mode Status Error Dual alarm is detected. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. DC *3 Transmission Error Transmission to component shown by sub code has failed. (Detecting this DTC does not necessarily mean actual failure.) If same sub code is recorded in other component, check harness for power supply and communication systems of all components shown by code. (If not, delete DTC and recheck.) DD *4 Master Reset (Momentary Interruption) After engine was started, master component was disconnected from system. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. If this error occurs frequently, replace radio receiver assembly. DE *4 Slave Reset (Momentary Interruption) After engine was started, component shown by sub code was disconnected from system. Check harness for power supply system of component shown by sub code. Check harness for communication system of component shown by sub code. DF *4 Master Error Due to defective condition of component with display, master function is switched to audio equipment. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. E0 *1 Registration Completion Instruction Error Registration completion instruction command from master cannot be received. Since this DTC is provided for engineering purposes, it may be set when no actual failure exists. E1 *1 Voice Processing Device ON Error Amp device records that amp output does not function even while source device is operating. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. E2 ON/OFF Instruction Parameter Error Error occurs in ON/OFF controlling command from master component. Replace radio receiver assembly. E3 *1 Registration Request Transmission Registration request command is output from component shown by sub code. Receiving connection check instruction, Registration request command is output from sub-master component. Since this DTC is provided for engineering purposes, it may be set when no actual failure exists. E4 *1 Multiple Frame Abort Multiple frame transmission is aborted. Since this DTC is provided for engineering purposes, it may be set when no actual failure exists. 22 RAM Error Abnormal condition of RAM is detected. Replace radio receiver assembly. HINT: *1: This DTC may be recorded depending on the battery condition or engine start voltage even if no failure is detected. *2: If the power connector is disconnected after the engine starts, this DTC is recorded after 180 seconds. *3: This DTC may be stored if the ignition key is turned to the START position again when the engine is already running. *4: This DTC may be stored if the ignition key is held in the START position for one minute or more before returning to the ON position. *5: The DTC is stored 210 seconds after the master component power supply connector is disconnected with the ignition switch in ACC or IG. Logical address: 62 (CD player) LOGICAL ADDRESS - CD PLAYER DTC Diagnosis Item Diagnostic Content Troubleshooting 42 No Disc Readout Disc cannot be read. Inspect CD Replace radio receiver assembly 44 CD player Error Error is detected in CD player. Replace radio receiver assembly 45 EJECT Error Disc cannot be ejected. Replace radio receiver assembly 46 Disc has scratches on the reverse surface CD has dirt or scratches on reverse side. Inspect CD If same code is detected, replace radio receiver assembly Logical address: 63 (In-dash CD player) LOGICAL ADDRESS - IN-DASH CD PLAYER DTC Diagnosis Item Diagnostic Content Troubleshooting 42 No Disc Readout Disc cannot be read. Inspect CD Replace radio receiver assembly 44 CD player Error Error is detected in CD player. Replace radio receiver assembly 45 EJECT Error Disc cannot be ejected. Replace radio receiver assembly 46 Disc has scratches on the reverse surface CD has dirt or scratches on reverse side. Inspect CD If same code is detected, replace radio receiver assembly 51 Elevator Error Mechanical error occurred during elevator operation. Replace radio receiver assembly 52 Clamp Error Error occurs on clamp Replace radio receiver assembly 440 (STEREO COMPONENT AMPLIFIER ASSEMBLY) Logical address: 01 (Communication control) LOGICAL ADDRESS - COMMUNICATION CONTROL DTC Diagnosis Item Diagnostic Content Troubleshooting D6 *1 Absence of Master Component in which this code is recorded was disconnected from system with ignition switch in ACC or ON. Alternatively radio receiver assembly was disconnected when this code was recorded. Check harness for power supply system of radio receiver assembly. Check harness for power supply system of stereo component amplifier assembly. Check harness for communication system of stereo component amplifier assembly. D7 Communication Check Error Component in which this code is recorded is or was disconnected from system after engine start. Alternatively radio receiver assembly was disconnected when this code was recorded. Check harness for power supply system of radio receiver assembly. Check harness for power supply system of stereo component amplifier assembly. Check harness for communication system of stereo component amplifier assembly. DC *2 Transmission Error Transmission to component shown by sub code has failed. (Detecting this DTC does not necessarily mean actual failure.) If same sub code is recorded in other component, check harness for power supply and communication systems of all components shown by code. (If not, delete DTC and recheck.) DD *3 Master Reset (Momentary Interruption) After engine was started, master component was disconnected from system. Check harness for power supply system of radio receiver assembly. Check harness for power supply system of stereo component amplifier assembly. Check harness for communication system of stereo component amplifier assembly. If this error occurs frequently, replace radio receiver assembly. DD *4 Master Error Due to defective condition of component with display, master function is switched to audio equipment. Error occurs in communication between sub-master (audio) and master component. Check harness for power supply of radio receiver assembly. Check harness for communication system of stereo component amplifier assembly. Check harness for communication system between multi-display assembly and sub-master component. E0 *1 Registration Completion Instruction Error Registration completion instruction command from master cannot be received. Since this DTC is provided for engineering purposes, it may be set when no actual failure exists. E1 *1 Audio processor ON Error While source device is operating, amp output stops. Check harness for power supply system of radio receiver assembly. Check harness for communication system of radio receiver assembly. E2 ON/OFF Instruction Parameter Error Error occurs in ON/OFF controlling command from master component. Replace radio receiver assembly. E3 *1 Registration Request Transmission Registration request command is output from slave component. Since this DTC is provided for engineering purposes, it may be set when no actual failure exists. HINT: *1: This DTC may be recorded depending on the battery condition or engine start voltage even if no failure is detected. *2: This DTC may be stored if the ignition key is turned to the START position again when the engine is already running. *3: This DTC may be stored if the ignition key is held in the START position for one minute or more before returning to the ON position. *4: If the device is reported as not existing during verification, check the power source circuit and AVC-LAN circuit for the device.

DESCRIPTION

This circuit sends an operation signal from the steering pad switch to the radio receiver assembly. If there is an open in the circuit, the audio system cannot be operated by the steering pad switch. If there is a short in the circuit, the same condition as that when the switch is continuously depressed occurs.

Therefore, the radio receiver assembly cannot be operated by the steering pad switch, and also the radio receiver assembly itself does not function.

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1. INSPECT RADIO RECEIVER ASSEMBLY Disconnect the R3 radio receiver assembly connector. Measure the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition SW1 (R3-7) - SWG (R3-6) No switch is pushed Approx. 100 k SW1 (R3-7) - SWG (R3-6) SEEK+ switch is pushed Approx. 0 SW1 (R3-7) - SWG (R3-6) SEEK - switch is pushed Approx. 0.3 k SW1 (R3-7) - SWG (R3-6) VOL+ switch is pushed Approx. 1 k SW1 (R3-7) - SWG (R3-6) VOL - switch is pushed Approx. 3.1 k SW2 (R3-8) - SWG (R3-6) No switch is pushed Approx. 100 k SW2 (R3-8) - SWG (R3-6) MODE switch is pushed Approx. 0 OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE NG: Go to next step
2. INSPECT STEERING PAD SWITCH LH (AU1, AU2, EAU) Disconnect the steering pad switch LH connector. Measure the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition AU1 - EAU No switch is pushed Approx. 100 k AU1 - EAU SEEK+ switch is pushed Approx. 0 AU1 - EAU SEEK - switch is pushed Approx. 0.3 k AU1 - EAU VOL+ switch is pushed Approx. 1 k AU1 - EAU VOL - switch is pushed Approx. 3.1 k AU2 - EAU No switch is pushed Approx. 100 k AU2 - EAU MODE switch is pushed Approx. 0 NG: REPLACE STEERING PAD SWITCH LH OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - RADIO RECEIVER ASSEMBLY) Disconnect the S8 spiral cable sub-assembly connector. Disconnect the R3 radio receiver assembly connector. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition SW1 (R3-7) - AU1 (S8-6) Below 1 SW2 (R3-8) - AU2 (S8-5) Below 1 SWG (R3-6) - EAU (S8-4) Below 1 SW1 (R3-7) - Body ground 10 k or higher SW2 (R3-8) - Body ground 10 k or higher SWG (R3-6) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE SPIRAL CABLE SUB-ASSEMBLY

Power is supplied to the radio receiver and steering pad switch illumination when the light control switch is in the TAIL or HEAD position.

The intensity of the radio receiver and steering pad switch illumination can be adjusted by the light control rheostat.

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1. SYSTEM CHECK Turn the light control switch to the TAIL or HEAD position. Check whether other displays and indicators such as the A/C switch indicator come on. OK: Other displays and indicators come on. NG: GO TO «LIGHTING SYSTEM»(ref-263665-S12912118742007091100000) OK: Go to Next Step
2. CHECK SYMPTOMS Check the symptom. Check whether the illumination for the radio receiver assembly or steering pad switch comes on. SYMPTOM REFERENCE Symptom Proceed To Illumination for radio receiver assembly does not come on. A Illumination for steering pad switch does not come on. B B: Go to step 5 A: Go to next step
3. CHECK RADIO RECEIVER ASSEMBLY Disconnect the R1 radio receiver assembly connector. Turn the light control switch to the TAIL or HEAD position. Measure the voltage. Standard: Built-in AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Light control switch TAIL Specified Condition ILL+ (R1-10) - Body ground Light control switch TAIL 10 to 14 V Standard: Separate AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Light control switch TAIL Specified Condition ILL+ (R1-2) - Body ground Light control switch TAIL 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - LIGHT CONTROL RHEOSTAT) Disconnect the R2 or R1 radio receiver assembly connector and R4 light control rheostat connector. Measure the resistance. Standard: Built-in AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition ILL- (R2-5) - (R4-3) Below 1 ILL- (R2-5) - Body ground 10 k or higher Standard: Separate AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition ILL- (R1-12) - (R4-3) Below 1 ILL- (R1-2) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
5. INSPECT STEERING PAD SWITCH LH NOTE: The vehicle is equipped with the SRS (Supplemental Restraint System) such as airbags. Before servicing (including removal or installation of parts), be sure to read the «PRECAUTION»(/toyota/tacoma/ii-2004-2011/remont/airbag/#supplemental-restraint-system) notice for the Supplemental Restraint System article. Disconnect the steering pad switch assembly connector. Connect the positive (+) lead to terminal ILL+ and the negative (-) lead to terminal EAU of the steering pad switch assembly connector. Check the illumination for the steering pad switch assembly. OK: Illumination for the steering pad switch assembly comes on. NG: REPLACE STEERING PAD SWITCH LH OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - RADIO RECEIVER ASSEMBLY) Disconnect the R3 radio receiver assembly connector. Disconnect the S8 spiral cable sub-assembly connector. Measure the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition SWG (R3-6) - EAU (S8-4) Below 1 NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. INSPECT SPIRAL CABLE SUB-ASSEMBLY Disconnect the spiral cable sub-assembly connector. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition EAU - EAU Below 1 ILL+ - ILL+2 Below 1 NG: REPLACE SPIRAL CABLE SUB-ASSEMBLY OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - DRIVER SIDE J/B)

Sound signals that have been amplified by the stereo component amplifier or radio receiver assembly (built-in amp) are sent to the speakers from the stereo component amplifier assembly or radio receiver assembly through this circuit.

If there is a short in this circuit, the stereo component amplifier assembly detects it and stops the output to the speakers.

Thus sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly or speakers.

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1. SYSTEM CHECK Check the system. Check whether the stereo component amplifier assembly is a built-in type or a separate type. TROUBLESHOOTING - AMPLIFIER Amplifier Type Proceed To Built-in AMP A Separate AMP B B: Go to step 6 A: Go to next step
2. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - SPEAKER ASSEMBLY) Disconnect the R2 and R1 radio receiver assembly connectors. Disconnect the speaker connectors. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition FL+ (R1-2) - S19-4 Below 1 FL- (R1-6) - S19-3 Below 1 FR+ (R1-1) - S20-4 Below 1 FR- (R1-5) - S20-3 Below 1 S19-1 - S15-2 Below 1 S19-2 - S15-1 Below 1 S20-1 - S16-2 Below 1 S20-2 - S16-1 Below 1 RL+ (R2-2) - S17-1 Below 1 RL- (R2-6) - S17-2 Below 1 RR+ (R2-1) - S18-1 Below 1 RR- (R2-3) - S18-2 Below 1 FL+ (R1-2) - Body ground 10 k or higher FL- (R1-6) - Body ground 10 k or higher FR+ (R1-1) - Body ground 10 k or higher FR- (R1-5) - Body ground 10 k or higher RL+ (R2-2) - Body ground 10 k or higher RL- (R2-6) - Body ground 10 k or higher RR+ (R2-1) - Body ground 10 k or higher RR- (R2-3) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT FRONT NO. 1 SPEAKER ASSEMBLY Measure the resistance between the terminals of the speaker. NOTE: The speaker should not be removed for checking. Standard: Approximately 4 NG: REPLACE FRONT NO. 1 SPEAKER ASSEMBLY OK: Go to next step
4. INSPECT FRONT NO. 2 SPEAKER ASSEMBLY Check that the malfunction disappears when another speaker in good condition is installed. OK: The malfunction disappears. HINT: Connect all the connectors to the speakers. When there is a possibility that either the left or right front speaker is defective, inspect by interchanging the left one and the right one. NG: REPLACE FRONT NO. 2 SPEAKER ASSEMBLY OK: Go to next step
5. INSPECT REAR SPEAKER ASSEMBLY Measure the resistance between the terminals of the speaker. NOTE: The speaker should not be removed for checking. Standard: Approximately 4 NG: REPLACE REAR SPEAKER ASSEMBLY OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
6. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - SPEAKER ASSEMBLY) Disconnect the S24 connectors from the stereo component amplifier assembly and speakers. Measure the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition FL+ (S24-6) - S19-4 Below 1 FL- (S24-17) - S19-3 Below 1 FR+ (S24-7) - S20-4 Below 1 FR- (S24-18) - S20-3 Below 1 S19-1 - S15-2 Below 1 S19-2 - S15-1 Below 1 S20-1 - S16-2 Below 1 S20-2 - S16-1 Below 1 RL+ (S24-4) - S17-1 Below 1 RL- (S24-13) - S17-2 Below 1 RR+ (S24-5) - S18-1 Below 1 RR- (S24-14) - S18-2 Below 1 FL+ (S24-6) - Body ground 10 k or higher FL- (S24-17) - Body ground 10 k or higher FR+ (S24-7) - Body ground 10 k or higher FR- (S24-18) - Body ground 10 k or higher RL+ (S24-4) - Body ground 10 k or higher RL- (S24-12) - Body ground 10 k or higher RR+ (S24-5) - Body ground 10 k or higher RR- (S24-14) - Body ground 10 k or higher WFL+ (S24-2) - Body ground 10 k or higher WFL- (S24-11) - Body ground 10 k or higher WFR+ (S24-3) - Body ground 10 k or higher WFR- (S24-12) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
7. INSPECT FRONT NO. 1 SPEAKER ASSEMBLY Measure the resistance between the terminals of the speaker. NOTE: The speaker should not be removed for checking. Standard: Approximately 4 NG: REPLACE FRONT NO. 1 SPEAKER ASSEMBLY OK: Go to Next Step
8. INSPECT FRONT NO. 2 SPEAKER ASSEMBLY Check that the malfunction disappears when another speaker in good condition is installed. OK: The malfunction disappears. HINT: Connect all the connectors to the speakers. When there is a possibility that either the left or right front speaker is defective, inspect by interchanging the left one and the right one. NG: REPLACE FRONT NO. 2 SPEAKER ASSEMBLY OK: Go to next step
9. INSPECT REAR SPEAKER ASSEMBLY Measure the resistance between the terminals of the speaker. NOTE: The speaker should not be removed for checking. Standard: Approximately 4 NG: REPLACE REAR SPEAKER ASSEMBLY OK: Go to next step
10. INSPECT NO. 1 SPEAKER ASSEMBLY WITH BOX Measure the resistance. NOTE: The speaker should not be removed for checking. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 1 - 3 2 2 - 4 2 NG: REPLACE NO. 1 SPEAKER ASSEMBLY WITH BOX OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

This circuit sends a signal to the stereo component amplifier to mute the noise. Because of that, the noise produced while changing the sound source ceases.

If there is an open in the circuit, noise can be heard from the speaker when changing the sound source. If there is a short in the circuit, even though the stereo component amplifier assembly is normal, no sound or only extremely quiet sound is produced.

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1. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY Measure the voltage. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition MUTE (S23-1) - Body ground Turn ignition switch to ACC, Audio system is playing --> Changing Above 3.5 V --> Below 1 V OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE NG: Go to next step
2. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER - STEREO COMPONENT AMPLIFIER) Disconnect the R1 radio receiver assembly connector and S23 stereo component amplifier assembly connector. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition MUTE (R1-7) - MUTE (S23-1) Always Below 1 MUTE (R1-7) - Body ground Always 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT RADIO RECEIVER ASSEMBLY Reconnect the R1 stereo component amplifier assembly connector. Turn the ignition switch to the ACC position. Measure the voltage. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition MUTE (R1-7) - Body ground Turn ignition switch to ACC 3.5 V or higher NG: REPAIR OR REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY OK: REPLACE RADIO RECEIVER ASSEMBLY

The radio receiver assembly sends sound signals to the stereo component amplifier assembly through this circuit. Sound signals that have been sent are amplified by the stereo component amplifier assembly, and then sent to the speakers.

If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly or speakers.

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1. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER - STEREO COMPONENT AMPLIFIER) Disconnect the R1 radio receiver assembly connector and S23 stereo component amplifier assembly connector. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition L+ (S23-3) - L+ (R1-9) Below 1 L- (S23-2) - L- (R1-19) Below 1 R+ (S23-5) - R+ (R1-8) Below 1 R- (S23-4) - R- (R1-18) Below 1 L+ (S23-3) - Body ground 10 k or higher L- (S23-2) - Body ground 10 k or higher R+ (S23-5) - Body ground 10 k or higher R- (S23-4) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

The radio receiver assembly sends sound signals to the stereo component amplifier assembly through this circuit.

Sound signals that have been sent are amplified by the stereo component amplifier assembly, and then sent to the speakers.

If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly or speakers.

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1. CHECK HARNESS AND CONNECTOR Disconnect the R1 radio receiver assembly connector and S23 stereo component amplifier assembly connector. Check the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition L+ (S23-3) - L+ (R1-9) Below 1 L- (S23-2) - L- (R1-19) Below 1 R+ (S23-5) - R+ (R1-8) Below 1 R- (S23-4) - R- (R1-18) Below 1 L+ (S23-3) - Body ground 10 k or higher L- (S23-2) - Body ground 10 k or higher R+ (S23-5) - Body ground 10 k or higher R- (S23-4) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

All audio system units that are connected to the AVC-LAN (communication bus) use it as the communication line by which they transmit switch signals.

When a +B short or GND short occurs in the AVC-LAN, the audio system fails to function normally, due to the discontinuation of communication.

In the AVC-LAN, the radio receiver assembly is the main communication center and has the correct resistance necessary for transmitting communication signals.

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1. INSPECT RADIO RECEIVER ASSEMBLY Disconnect the R1 radio receiver assembly connector. Measure the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition TX+ (R1-5) - TX (R1-15) Always 60 to 80 NG: REPLACE RADIO RECEIVER ASSEMBLY OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER - STEREO COMPONENT AMPLIFIER) Disconnect the R1 radio receiver assembly connector and S23 stereo component amplifier assembly connector. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition TX+ (S23-8) - TX+ (R1-15) Below 1 TX+ (S23-7) - TX- (R1-15) Below 1 TX+ (R1-5) - Body ground 10 k or higher TX+ (R1-5) - Body ground 10 k or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY NG: REPLACE RADIO RECEIVER ASSEMBLY OK: END

This circuit provides power to the radio receiver assembly.

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1. INSPECT RADIO RECEIVER ASSEMBLY Check the resistance. Standard: Built-in AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition GND (R1-7) - Body ground Constant Below 1 Standard: Separate AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition GND (R1-20) - Body ground Constant Below 1 Turn the ignition switch to the ACC position. Measure the voltage. Standard: Built-in AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition B (R1-4) - GND (R1-7) Constant 10 to 14 V ACC (R1-3) - GND (R1-7) Ignition switch ACC or ON 10 to 14 V Standard: Separate AMP TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition B (R1-1) - GND (R1-20) Constant Below 1 ACC (R1-11) - GND (R1-20) Ignition switch ACC or ON 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

This circuit provides power to the stereo component amplifier assembly.

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1. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY Disconnect the S23 and S24 stereo component amplifier assembly connectors. Check the resistance. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition E (S24-16) - Body ground Always Below 1 GND (S24-15) - Body ground Always Below 1 Turn the ignition switch to the ACC position. Measure the voltage. Standard TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition B+ (S24-1) - GND (S24-15) Always 10 to 14 V +B2 (S24-10) - GND (S24-15) Always 10 to 14 V ACC (S23-12) - GND (S24-15) Ignition switch ACC 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - BATTERY OR BODY GROUND) OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

Scheme 39

Scheme 40

Scheme 41

Scheme 42

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
2. REMOVE AIR CONDITIONING CONTROL ASSEMBLY (See «REMOVAL»(ref-263671-S10551953862007091100000) )
3. REMOVE RADIO RECEIVER ASSEMBLY Remove the 4 bolts. Disconnect the connector and remove the radio receiver assembly with bracket.
4. REMOVE NO. 1 RADIO BRACKET Remove the 4 bolts and the No.1 radio bracket.
5. REMOVE NO. 2 RADIO BRACKET Remove the 4 bolts and the No. 2 radio bracket.

Scheme 43

Scheme 44

Scheme 45

1. INSTALL NO. 2 RADIO BRACKET Install the No. 2 radio bracket with the 4 bolts. Torque: 2.5 N*m (25 kgf*cm, 22 in.*lbf)
2. INSTALL NO. 1 RADIO BRACKET Install the No. 1 radio bracket with the 4 bolts. Torque: 2.5 N*m (25 kgf*cm, 22 in.*lbf)
3. INSTALL RADIO RECEIVER ASSEMBLY Connect the connector. Install the radio receiver assembly with bracket with the 4 bolts. Torque: 2.5 N*m (25 kgf*cm, 22 in.*lbf)
4. INSTALL AIR CONDITIONING CONTROL ASSEMBLY (See «INSTALLATION»(ref-263671-S05767437042007091100000) )
5. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL Torque: 3.9 N*m (40 kgf*cm, 35 in.*lbf)

Scheme 46

Scheme 47

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
2. REMOVE V-BANK COVER (See «REMOVAL»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-1gr-fe) )
3. REMOVE AIR CLEANER ASSEMBLY (See «REMOVAL»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-1gr-fe) )
4. REMOVE RADIO SETTING CONDENSER Disconnect the connector. Remove the tape and the radio setting condenser.

Scheme 48

1. INSTALL RADIO SETTING CONDENSER Disconnect the connector. Wind new vinyl tape around the hose and install the radio setting condenser.
2. INSTALL AIR CLEANER ASSEMBLY (See «INSTALLATION»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-1gr-fe) )
3. INSTALL V-BANK COVER (See «INSTALLATION»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-1gr-fe) )
4. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL Torque: 3.9 N*m (40 kgf*cm, 35 in.*lbf)

Scheme 49

Scheme 50

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
2. REMOVE AIR CLEANER ASSEMBLY (See «REMOVAL»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-2tr-fe) )
3. REMOVE RADIO SETTING CONDENSER Disconnect the connector. Remove the tape and the radio setting condenser.

Scheme 51

1. INSTALL RADIO SETTING CONDENSER Disconnect the connector. Remove the tape and the radio setting condenser.
2. INSTALL AIR CLEANER ASSEMBLY (See «INSTALLATION»(/toyota/tacoma/ii-2004-2011/remont/testing-diagnostics/#engine-control-system-2tr-fe) )
3. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL Torque: 3.9 N*m (40 kgf*cm, 35 in.*lbf)

Scheme 52

See also:
• PRECAUTION
• REMOVAL
• REMOVAL
• REMOVAL