Toyota Sienna Quiz
Audio / visual

Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

In this manual: Audio / visual
Introduction — 55Service specifications — 7Maintenance — 7Engine — 264U151e automatic transaxle — 108Transfer — 19Propeller shaft — 8Drive shaft — 14Differential — 16Axle — 18Suspension — 37Tire and wheel — 54Brake control — 141Parking brake — 16Steering Column — 11Power steering — 18Air conditioning — 106Supplemental restraint system — 146Seat belt — 22Theft deterrent — 14Engine immobiliser — 17Cruise control — 65Lighting — 61Wiper and washer — 13Door lock — 42Meter — 28Audio / visual — 94Navigation — 108Park assist / monitoring — 33Horn — 5Garage door opener — 42GR-FE Engine control system — 126Supplemental restraint system — 147Other system — 14Windshield / windowglass — 43Mirror — 23Instrument panel — 6Seat belt — 22Seat — 92Engine hood / door — 104Exterior — 39Interior — 5Sliding roof — 9Multiplex communication — 18Can communication — 23
9steps
~54min
2/5difficulty
Done 0 of 9

DESCRIPTION This circuit is necessary for the ASL (Auto Sound Leveliser) built into the radio receiver.

Speed signals are received from the combination meter and used for the ASL.

The ASL function automatically adjusts the sound data in order to enable hearing the clear audio sound even when vehicle noise increases (as vehicle noise increases, the volume is turned up etc.).

HINT:

  • A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal is changed to a pulse signal at the transistor in the combination meter. Each ECU controls the respective system based on the pulse signal.
  • If a short occurs in an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM

WIRING DIAGRAM

INSPECTION PROCEDURE

1 CHECK OPERATION OF SPEEDOMETER

  1. Drive the vehicle and check if the function of the speedometer on the combination meter is normal.

OK: Actual vehicle speed and the speed indicated on the speedometer are the same.

HINT: the vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

2 INSPECT RADIO RECEIVER

INSPECT RADIO RECEIVER
  1. Disconnect the radio receiver connector.
  2. Measure the voltage.
  3. Jack up either one of the drive wheels.
  4. Move the shift lever to the neutral position.
  5. Turn the ignition switch to the ON position.

*1: 6 Speaker without Rear Seat Entertainment System.

*2: 6 Speaker with Rear Seat Entertainment System.

INSPECT RADIO RECEIVER
  1. Measure the voltage between terminal SPD of the radio receiver and body ground when the drive wheels are turned slowly.

OK: Voltage pulses as shown in the illustration.

3 CHECK HARNESS AND CONNECTOR (COMBINATION METER - RADIO RECEIVER)

CHECK HARNESS AND CONNECTOR (COMBINATION METER - RADIO RECEIVER)
  1. Disconnect the radio receiver connector and combination meter connector.
  2. Measure the resistance according to the value(s) in the table below.

Standard resistance

Standard resistance

*1: 6 Speaker without Rear Seat Entertainment System.

*2: 6 Speaker with Rear Seat Entertainment System.

4 CHECK HARNESS AND CONNECTOR

CHECK HARNESS AND CONNECTOR
  1. Disconnect the radio receiver connector and combination meter connector.
  2. Measure the resistance according to the value(s) in the table below.

Standard resistance

HINT: If the resistance between terminal SPD and body ground is less than 10 kΩ, there may be a short in a wire harness, connector, or an ECU that is connected to the SPD signal wire.

*1: 6 Speaker without Rear Seat Entertainment System.

*2: 6 Speaker with Rear Seat Entertainment System.

REPLACE COMBINATION METER

Test yourself

A quick Toyota Sienna quiz: every answer comes with an explanation and a link to the manual page.