Toyota Sienna Service Manual: Speed Signal Circuit
DESCRIPTION
The clearance warning ECU receives the vehicle speed signal from the combination meter.
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
INSPECTION PROCEDURE
1 CHECK OPERATION OF SPEEDOMETER
- Drive the vehicle and check if the function of the speedometer in the combination meter is normal.
OK: Actual vehicle speed and the speed indicated on the speedometer are the same.
HINT: The vehicle speed signal is normal when the indication on the speedometer is normal.
2 INSPECT CLEARANCE WARNING ECU
- Disconnect the clearance warning ECU connector C9.
- Measure the voltage.
- Jack up either one of the drive wheels.
- Move the shift lever to the neutral position.
- Turn the ignition switch to the ON position
- Measure the voltage between terminal SPD of the clearance warning ECU and body ground when a drive wheel is turned slowly.
OK: Voltage pulses as shown.
3 CHECK HARNESS AND CONNECTOR (COMBINATION METER - CLEARANCE WARNING ECU)
- Disconnect the combination meter C10 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
4 CHECK HARNESS AND CONNECTOR (COMBINATION METER AND EACH ECU - BODY GROUND)
- 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 ECU.
REPLACE COMBINATION METER
Park / Neutral Position Switch Circuit
DESCRIPTION
The clearance warning ECU receives the reverse or park position signal from
the park / neutral position
switch.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT CLEARANCE WARNING E ...
Back Sonar Sensor LH Circuit
DESCRIPTION
An ultrasonic sensor consists of a sensor portion that transmits and receives
ultrasonic waves and a preamplifier
that amplifies them. The ultrasonic sensor outputs the ultrasonic wave ...
Other materials:
Checking tires
Check if the treadwear indicators are showing on the tires. Also check
the tires for uneven wear, such as excessive wear on one side of the
tread. Check the spare tire condition and pressure if not rotated.
New tread
Worn tread
Treadwear indicator
The location of treadwear indicator ...
Knock Sensor 1 Circuit Low Input
DESCRIPTION
A flat type knock sensor (non-resonant type) has a structure that can detect
vibrations over a wide band of
frequencies: between approximately 6 kHz and 15 kHz.
Knock sensors are fitted onto the engine block to detect engine knocking.
The knock sensor contains a piezoelectr ...
Inspection
1. INSPECT FRONT STABILIZER LINK ASSEMBLY LH
(a) As shown in the illustration, flip the ball joint stud
back and forth 5 times, before installing the nut.
(b) Using a torque wrench, turn the nut continuously at
a rate of 2 to 4 seconds per 1 turn and take the
torque reading on the 5th turn.
...
