2008 Toyota Prius BaseFACTORY OEM SERVICE PROCEDURE

Problem Symptoms Table

HINT:

  • Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
  • Inspect the fuses and relays related to this system before inspecting the suspected areas below.

Audio function 

AUDIO FUNCTION

Symptom Suspected area See
Pressing power switch does not turn on system. 1. Proceed to "PRESSING POWER SWITCH DOES NOT TURN ON SYSTEM " PRESSING POWER SWITCH DOES NOT TURN ON SYSTEM 
2. Radio receiver power source circuit RADIO RECEIVER POWER SOURCE CIRCUIT 
3. Multi-display power source circuit MULTI-DISPLAY POWER SOURCE CIRCUIT 
4. AVC-LAN circuit AVC-LAN CIRCUIT 
5. Radio receiver TERMINALS OF ECU 
6. Multi-display TERMINALS OF ECU 
Panel switch does not function. 1. Steering pad switch circuit STEERING PAD SWITCH CIRCUIT 
2. AVC-LAN circuit AVC-LAN CIRCUIT 
3. Radio receiver TERMINALS OF ECU 
No sound can be heard from speakers (audio is mute). 1. AVC-LAN circuit AVC-LAN CIRCUIT 
2. Radio receiver power source circuit RADIO RECEIVER POWER SOURCE CIRCUIT 
3. Multi-display power source circuit MULTI-DISPLAY POWER SOURCE CIRCUIT 
4. Proceed to "NO SOUND CAN BE HEARD FROM SPEAKERS " NO SOUND CAN BE HEARD FROM SPEAKERS 
5. Stereo component amplifier power source circuit STEREO COMPONENT AMPLIFIER POWER SOURCE CIRCUIT 
6. Proceed to "SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER " SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER 
7. Speaker circuit SPEAKER CIRCUIT 
8. Proceed to "MUTE SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER " MUTE SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER 
9. Stereo component amplifier TERMINALS OF ECU 
10. Radio receiver TERMINALS OF ECU 
11. Multi-display TERMINALS OF ECU 
Sound quality is bad in all modes (Volume is too low). 1. Proceed to "POOR SOUND QUALITY IN ALL MODELS (LOW VOLUME) " POOR SOUND QUALITY IN ALL MODES (LOW VOLUME) 
2. Speaker circuit SPEAKER CIRCUIT 
3. Proceed to "SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER " SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER 
4. Proceed to "MUTE SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER " MUTE SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO COMPONENT AMPLIFIER 
Auto sound levelizer does not function (9 speaker system). Proceed to "VEHICLE SPEED SIGNAL CIRCUIT BETWEEN STEREO COMPONENT AMPLIFIER AND COMBINATION METER " VEHICLE SPEED SIGNAL CIRCUIT BETWEEN STEREO COMPONENT AMPLIFIER AND COMBINATION METER 
Auto sound levelizer does not function (6 speaker system). Proceed to "VEHICLE SPEED SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND COMBINATION METER " VEHICLE SPEED SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND COMBINATION METER 
External device sound cannot be heard or sound quality is bad (Stereo jack is used). 1. Radio receiver power source circuit RADIO RECEIVER POWER SOURCE CIRCUIT 
2. Proceed to "SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO JACK ADAPTER " SOUND SIGNAL CIRCUIT BETWEEN RADIO RECEIVER AND STEREO JACK ADAPTER 
3. Stereo jack adapter -
4. Radio receiver TERMINALS OF ECU 
Abnormal noise occurs. 1. Proceed to "NOISE OCCURS " NOISE OCCURS 
2. Stereo component amplifier TERMINALS OF ECU 
3. Radio receiver TERMINALS OF ECU 
Radio broadcast cannot be received or poor reception. Proceed to "RADIO BROADCAST CANNOT BE RECEIVED OR POOR RECEPTION " RADIO BROADCAST CANNOT BE RECEIVED OR POOR RECEPTION 
CD cannot be inserted/played or CD is ejected right after insertion. 1. Radio receiver power source circuit RADIO RECEIVER POWER SOURCE CIRCUIT 
2. Proceed to "CD CANNOT BE INSERTED/ PLAYED OR CD IS EJECTED RIGHT AFTER INSERTION " CD CANNOT BE INSERTED/ PLAYED OR CD IS EJECTED RIGHT AFTER INSERTION 
CD cannot be ejected. 1. Radio receiver power source circuit RADIO RECEIVER POWER SOURCE CIRCUIT 
2. Proceed to "CD CANNOT BE EJECTED " CD CANNOT BE EJECTED 
Sound quality is bad only when CD is played. Proceed to "SOUND QUALITY IS BAD ONLY WHEN CD IS PLAYED (VOLUME IS TOO LOW) " SOUND QUALITY IS BAD ONLY WHEN CD IS PLAYED (VOLUME IS TOO LOW) 
CD sounds skips. Proceed to "CD SOUND SKIPS " CD SOUND SKIPS 
Radio receiver or multi-display cannot be illuminated at night. Illumination circuit ILLUMINATION CIRCUIT 

Steering pad switch function 

STEERING PAD SWITCH FUNCTION

Symptom Suspected area See
Audio system cannot be operated with steering pad switch. 1. Steering pad switch circuit STEERING PAD SWITCH CIRCUIT 
2. Radio receiver TERMINALS OF ECU 
Steering pad switch cannot be illuminated at night. Illumination circuit ILLUMINATION CIRCUIT 
Cellular phone registration failure, phone directory transfer failure. Proceed to "CELLULAR PHONE REGISTRATION FAILURE, PHONE DIRECTORY TRANSFER FAILURE " CELLULAR PHONE REGISTRATION FAILURE, PHONE DIRECTORY TRANSFER FAILURE 
Cellular phone cannot send / receive. 1. Proceed to CELLULAR PHONE CANNOT SEND / RECEIVE  CELLULAR PHONE CANNOT SEND / RECEIVE 
2. Steering pad switch circuit STEERING PAD SWITCH CIRCUIT 
3. Multi-display TERMINALS OF ECU 
Cannot call in a certain place. Proceed to "CANNOT CALL IN A CERTAIN PLACE " CANNOT CALL IN A CERTAIN PLACE 
The other caller's voice cannot be heard, is too quiet, or distorted. 1. Proceed to "THE OTHER CALLER'S VOICE CANNOT BE HEARD, IS TOO QUIET, OR DISTORTED " THE OTHER CALLER'S VOICE CANNOT BE HEARD, IS TOO QUIET, OR DISTORTED 
2. Multi-display TERMINALS OF ECU 
The other caller cannot hear your voice, or your voice is too quiet or distorted. 1. Proceed to "THE OTHER CALLER CANNOT HEAR YOUR VOICE, OR YOUR VOICE IS TOO QUIET OR DISTORTED " THE OTHER CALLER CANNOT HEAR YOUR VOICE, DISTORTED OR YOUR VOICE IS TOO QUIET OR DISTORTED 
2. Microphone circuit between overhead J/B and multi-display MICROPHONE CIRCUIT BETWEEN OVERHEAD J/B AND MULTI-DISPLAY 
3. Microphone -
4. Microphone amplifier -
5. Multi-display TERMINALS OF ECU 
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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