Toyota Yaris 2006 Car Radio

  1. Pull the two side bands, starting from the bottom edge.
  2. Remove the four screws.
  3. Unlock the three interlocking snap in at the top: push the tabs with your finger while you pull the frame.
  4. Pull the radio block, releasing the four mounting pin-push (pink color).
  5. Release the three connectors and the antenna plug.

Steering wheel commands

There are five buttons at the steering wheel: volume +, volume -, channel up, channel down and mode. At the radio side there are only three wires connected to the 20 pin connector.

Here it is the schematic:

Toyota Yairs steering wheel commands: schematic Toyota Yairs steering wheel commands: radio connector pinout

With a multimeter we read the resistance values at the radio receiver connector while pressing each button:

Resistance at SWG - SW1
No buttons pressed 100 kΩ
Seek + 0 Ω
Seek - 329 Ω
Vol + 1000 Ω
Vol - 3110 Ω
Resistance at SWG - SW2
No buttons pressed 100 kΩ
Mode 0 Ω

so we calculated the resistor values:

Steering Wheel Commands Resistors
R1 100 kΩ
R2 100 kΩ
R3 330 Ω
R4 680 Ω
R5 2200 Ω